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S O M T A U S E R G U I D E

SOMTA TECHNICAL SERVICES

FULL SPECIFICATIONS IN SOMTA CATALOGUES

PRODUCT RANGE STANDARDS & SPECIALS

TechnicalAssistance

This handbook is intended to help you get maximum performance fromSOMTA cutting tools. Whilst the information covers most common uses andproblems it is not possible to deal with every situation. Our trained salesrepresentatives are available to further assist and advise, fully backed up byfactory technical services.

SOMTA TOOLS (PTY) LTD is a world class manufacturer producing precision

cutting tools to international standards and specifications which include British Standard, DIN, ISO, ANSI and JIS. Full details of specifications arelisted in our catalogues which are available from leading Industrial Distributors or directly from the Somta factory.

The SOMTA range consists of over 7 000 standard items and we have a cutting tool available for almost every application. Sometimes a specialtool is needed and our product engineers at the SOMTA factory can designa special purpose tool to do the job. These can also be manufactured tocustomers’ specifications or to a sample.

IntroductionManufacturers & Suppliers of Drills, Reamers, End Mills,

Bore Cutters, Taps & Dies, Toolbits, Solid Carbide Tooling,

Carbide Insert Tooling, Custom Tools and Surface Coatings

Profile

SOMTA TOOLS vision as a world class provider of cutting tools, is supported

by ISO 9001 accreditation.

SOMTA TOOLS specialises in the design and manufacture of drills, reamers,

milling cutters, toolbits, threading tools and custom tools for the industrialand “DIY” markets, offering the innovative range of Balzers BALINIT highperformance coatings on all cutting tools.

®

The CompanySOMTA TOOLS factory in Pietermaritzburg manufactures over 7 000 standard

items and a further 3 000 made-to-order items to serve the domestic and export markets in over 70 countries worldwide.

The ProductSOMTA TOOLS standard catalogue range of

precision cutting tools are supplied through aextensive network of industrial distributors,backed up by technical sales representativeswho are available to provide technical assistance where required.

Should a special production applicationrequiring specially designed customtooling be requested, Somta is able to provide a full technical design service.

Manufacturers of precision industrial andDIY coated cutting toolsStandard and custom designed tooling

The major functions the end user,

apprentice or student can expect from

Somta’s technical representatives and

design departments are as follows:

• Provision of technical literature to assist

with the correct application of Somta’s

tooling.

• Assistance with and solution of any tooling

design and application relating to Somta’s

custom tooling.

• Advice, suggestions and

recommendations on product

improvement or innovation. Provision of

training in the use, care and

resharpening of high speed steel cutting

tool on request.

• Liaison between the customer and

Somta’s factory estimator and production

staff, to deliver the required tooling on

time according to specification, to the

customers complete satisfaction.

Contact our technical department on

for technical assistance if experiencing

a cutting tool problem.

Tel: +27 33 355 6600 or

e-mail: [email protected]

AN EXAMPLE OF BEFORE

AND AFTER REGRINDING

State ofthe art . . .

Somta has an integrated

state of the art

Balzers PVD Rapid

Coating Systemin it’s manufacturing

programme, offering the

innovative range of

®Balzers BALINIT

high performance

coatings on all cutting

tools.

Applicationproducts

SOMTA Colour Band Application range of drills and taps is specially designed to optimize your machining performances. Each range has been designed with different cutting geometries and surface treatments to ensure optimum tool performance for each specific material category.

This outstanding development increases drill cutting efficiency by means of greatly improved chip control. A chipbreaker rib is positioned along the length of the flutes, which curls and breaks long chip forming material into small manageable chips for easier evacuation. There is no clogging of chips in the flutes, as small chips flow freely along the flutes. The chipbreaker drill thus cuts more freely than standard drills.

MTS Chipbreaker Drills

Colour Band Range

Solid Carbide End Mills for Aluminium

Somta's high efficiency carbide end mill range with optimal flute geometry provides all the required features for high performance machining of aluminium, with the added benefits of greater stock removal rates at high speeds and feeds, excellent surface finish quality and extended tool life.

Reamer Tool Range

Established in 1954, Somta offers a range of high quality standard reamer products and custom reaming solutions. From closest tolerance precision machining of extremely accurate holes through to enlargement, alignment and deburring of holes for construction, assembly and general purpose applications. We have a product or a solution to satisfy your specific engineering requirements.

Application

UD Ultra Parabolic Twist Drills

A comprehensive range of heavy duty drills designed with improved point and flute geometries for enhanced penetration and chip removal in long chip forming, short chip forming and abrasive material groups. This range of Parabolic Flute Ultra Drills are designed to meet the challenges of a broad spectrum of difficult drilling applications.

products

Somta's Solid Carbide Tooling Range is a comprehensive family of solid carbide stub and jobber length drills, 2 and 4 flute end mills and ball nose end mills, in both regular and long series, and almost any special form carbide tooling.

Solid Carbide Tooling (Standard Range)

Applicationproducts

Solid Carbide VariCut End Mills

Somta's new "Vari-Style" End Mill, VariCut has a new patent pending tool design. This unique design uses a new core form and a new reinforced end geometry with unequal flute spacing which enables it to remove the most amount of material in the least amount of time with an excellent surface finish. On Stainless, or Titanium, it will match or outperform any other 4 flute "Vari-Style" End Mill in the market.

IF YOU CANNOT FIND AN ANSWER TO YOUR PROBLEM INTHIS BOOKLET PLEASE CONTACT THE SOMTA FACTORY

Solid Carbide Hard Material End Mills

A range of high performance finishing end mills for operation on hard materials up to 52HRC (512HB), plus Somta's Hi-Feed end mill with patent pending geometry that removes the most amount of material in the least amount of time combined with extended tool life, for use on hard and super hard steels up to 62HRC (684HB).

Standardproducts

Morse Taper Shank Drills

Reamers, Countersinks& Counterbores

Bore Cutters

Toolbits

Straight Shank Drills

Shank Cutters

Threading Tools

Standardproducts

ContentsCUTTING TOOL MATERIALS

SURFACE TREATMENTS 3-4

DRILLS

- Selecting the correct drill 5-10

- Drill nomenclature 11-12

- Types of spiral (or helix) angles 12

- Drill point styles 13-15

- Flute forms 15

- Common re-sharpening errors 16-17

- Standard morse taper shank 17

- How to order specials 18-20

- Cutting diameter tolerance 21

- Core drilling

- Core drill nomenclature 22-23

- A guide to core drilling 23

- Centre drills

- Centre drill nomenclature 24

- Selecting the correct centre drill 25

- The correct use of centre drills 26

- The correct use of drills 27-28

- Drilling problems: Causes and solutions 29-32

- Drill feed curve chart 32-33

- Drill technical data 34-35

- UD drill technical data 36-37

- Solid carbide drills technical data 38-39

REAMERS, COUNTERSINKS & COUNTERBORES

- Selecting the correct reamer, countersink & counterbore 40-41

- Reamers

- Reamer nomenclature 42

- The correct use of reamers 43-44

1-2

Contents - Re-sharpening reamers 44-45

- Counterbores

- Counterbore nomenclature 45

- The correct use of counterbores 46

- Re-sharpening counterbores 46

- Countersinks

- Countersink nomenclature 47

- The correct use of countersinks 47

- Re-sharpening countersinks 47

- Reaming problems: Causes and solutions 48-49

- Reamer technical data 50-51

TAPS

- Selecting the correct tap 52-58

- Tap nomenclature 59-60

- Standard lead (chamfer angles) 61

- Thread forms 62-67

- Recommended tapping drill sizes 68-74

- Fluteless taps 75

- Correct use of taps 76-80

- Re-sharpening taps 80

- Tapping problems: Causes and solutions 81-87

- Tap technical data 88-91

- CBA tap technical data 92-93

- Tap peripheral speed to rpm conversion chart 94-95

CUTTERS

- Shank cutters

- Selecting the correct shank cutter 96-100

- Shank cutter nomenclature 101-105

- Shank options 106

- Hints for successful shank cutter usage 107

Contents - Arbor mounted cutters

- Selecting the correct arbor mounted cutter 108-110

- Arbor mounted cutter nomenclature 111-114

- Hints for successful arbor mounted cutter usage 115-116

- Slitting saws

- Selecting the correct slitting saw 117

- Slitting saw nomenclature 118

- Hints for successful slitting saw usage 119

- Climb or conventional milling 120-121

- Problem solving 122-123

- Difficult to machine materials 124

- Re-sharpening and care of milling cutters 125

- Solid carbide end mills technical data 126-133

- Cutter technical data 134-137

- Feeds per tooth 138-145

- Speed and feed formula 146

GENERAL INFORMATION

- Tolerances 147

- Peripheral speed to rpm conversion chart 148-149

- Inch-millimeter conversion table 150-151

- Approximate hardness and tensile strength conversions 152

- Hardness conversion chart for high speed steel 153

- Useful formulae 154-158

- Useful tapers 159

- Morse taper and brown and sharpe tapers 160

- Conversion factors 161

- Number and letter drill sizes 162

NOTES 163-166

1WORLD CLASS CUTTING TOOLS

Somta cutting tools are manufactured from the finest steelsavailable.

Solid CarbideSub-micron or ultra fine cabide grade of European origin. Highstock removal rates with excellant rigidity at high speeds andfeeds and extended wear life are the major benefits of thismaterial.

High Speed SteelHigh Speed Steel contains various elements such as Molybdenum,Tungsten, Cobalt and Vanadium and must be specially heattreated to produce the ideal combination of strength, toughnessand wear resistance. The heat treatment process is controlledby our Metallurgical laboratory using advanced computerisedand electronic instrumentation.

SOMTA products are manufactured from one of the followingHigh Speed Steels depending on the product and application.

Hardness (HRC)63 - 6564 - 66

66 - 68.5(70)64-66

C0.90.91.11.2

Cr444

3.9

W66

1.57

Mo55

9.55.2

V221

2.7

Co-58-

HSSHSS-Co5HSS-Co8HSSE-V3

CUTTING TOOL MATERIALS

2 WORLD CLASS CUTTING TOOLS

HSS (M2) is the standard High Speed Steel and is used wheretoughness is important, together with a good standard of wearresistance and red hardness.

HSS-Co5 (M35) is a development of M2 and contains 5% cobaltwhich gives improved hardness, wear resistance and redhardness. It may be used when cutting higher strength materials.

HSS-Co8 (M42) can be heat treated to very high hardnesslevels of up to 70 HRC (1 000 HV) although normally a slightlylower figure will be employed to retain toughness. This steel isideal for machining higher strength materials and work hardeningalloys such as stainless steels, nimonic alloys etc. Despite itshigh hardness, M42 has good grindability characteristics due tolower vanadium content.

HSSE-V3 material is mainly used in the manufacture of machinetaps because of its good wear resistance, good grindingcapabilities, high hardness and excellent toughness.


Bright FinishA bright finish tool has no surface treatment and is suitable forgeneral purpose use.

Blue FinishA blue finish is achieved by steam tempering - a thermal pro-cess which imparts a non-metallic surface to the tool. Thissurface is porous and by absorbing lubricant, helps preventrusting, reduces friction and cold welding, resulting in increasedtool life. Steam tempered products can successfully be used atslightly increased machining rates or on more difficult to machinematerials.

Gold Oxide FinishThis is a metallic brown coloured surface treatment achievedby a low temperature temper and is normally only used oncobalt products for identification purposes.

NitridingNitriding imparts a hard surface to the tool and is used forprolonging tool life and machining difficult to machine materials.Because nitriding makes the edge more brittle, care must beexercised in the type of application.Nitrided tools are normally also steam tempered.

Titanium Nitride Coating (TiN)TiN coating is a very hard, gold coloured surface coating a fewmicrons thick which is applied by means of a complex process,called Physical Vapour Deposition (PVD), by advanced modernequipment. The coating is non-metallic and therefore reducescold welding.

In certain applications increased speed and feed rates can beachieved because of:

(a) The hardness of the coating.

SURFACE TREATMENTS


(b) The reduction in cutting force required due to a decrease infriction between the tool and the workpiece.

Tool performance will deteriorate after re-sharpening.

TiCN (Titanium Carbonitride)The addition of carbon to TiN results in a significant increase inthe hardness of TiCN over TiN. TiCN also has a much lowercoefficient of friction which enhances the surface finish ofcomponents machined with TiCN coated tools, higher productivitycan be achieved on a wide range of materials but, in particularstainless steel, titanium and nickel based alloys. It is nowgenerally accepted that TiCN coating has been superseded byTiAlN for most machining applications.

TiAlN (Titanium Aluminium Nitride)In addition to a higher hardness than both TiN and TiCN thealuminium in the coating imparts a much greater oxidation stability.This is as a result of a very thin film of (Aluminium Oxide) beingformed on the surface of the TiAlN. The film is self repairing,leading to additional increased service life. These improvementsallow the coating to withstand much higher temperatures whichin turn allows increased cutting conditions, especially usefulwhen machining Cast Iron and tough steels.

Carbide CoatingsThe material and properties ofthe coating used is bestmatched to solid carbidecutting tool substrate materialallowing the coated solidcarbide tool to be successfullyemployed under the extremeconditions of hard machiningand typically permits muchfaster and more economicalmachining of dies in hard andsuper hard steels.


DRILLS

SELECTING THE CORRECT DRILL

Straight Shank DrillsThe following are available ex-stock from Somta.

Stub Drills

Solid Carbide for high production drilling.

Coolant Feed Solid Carbide for high production drilling.

A robust drill suited to portable drill application.

UDL for use on CNC machines where high productivity andaccurate holes are required.

Jobber Drills

Solid Carbide for high production drilling.

Coolant Feed Solid Carbide for high production drilling.

For precision drilling.

For light industrial drilling.

For drilling high tensile steels and other difficult materials.

DRILLS


UDL for use on CNC machines where high productivity andaccurate holes are required.

CBA - Yellow Band Quick Spiral for drilling Aluminium.

CBA - Blue Band RF for drilling Stainless Steel (VA).

CBA - Green Band NDX for drilling Carbon Steel.

CBA - Red Band UDS for drilling Tough Treatable Steel.

CBA - White Band UDC for drilling Cast Iron.

Double Ended Sheet Metal / Body Drills

Double ended self centering drill designed to produceaccurate holes in thin materials.

Reduced Shank (Electricians) Drills

For general purpose drilling.

Long Series Drills

For general purpose long reach drilling.

UDL for use on CNC machines where high productivity andaccurate holes are required. High performance deep holedrilling.


Extra Length Drills

For extra deep hole drilling.

UDL for use on CNC machines where high productivity andaccurate holes are required. High performance extra deephole drilling.

NC Spotting Drills

For accurate positioning of holes. Ideal for CNC lathes.Alternative to using centre drills.

Centre Drills - Form A, B, R and American Standard

For general centering operations on workpieces requiringadditional machining between centres.

Masonry Drills

For drilling concrete, brick and tile.

Heavy Duty SDS Plus Drills

For drilling concrete, brick and tile.

Cutting tools may shattereye protection should be worn


Morse Taper Shank DrillsThe following are available ex-stock from Somta.


For general purpose drilling.

For general purpose drilling in difficult materials.

MTS Extra Length Drills

For extra deep hole drilling.

MTS Chipbreaker Drills

High performance production drilling.

MTS Oil Tube Chipbreaker Drills

High performance production drilling.

MTS Armour Piercing Drills

Heavy duty drilling in work hardening and heat treated steels.

MTS Rail Drills

For drilling manganese rails and other tough steels.


MTS Core Drills

For enlarging diameters of existing holes whether drilled,punched or cast.

Sorgers

A wood auger for drilling all types of wood.

SpecialsDrills for special Applications.

Tanged Jobber Drills

Designed to fit tang drive sleeve.

Drill Reamers

For drilling and reaming holes in one operation (hole tolerancewider than H7).

Sheet Metal Drills

Self centering drill designed to produce accurate holes in thinmaterials.

UDC Jobber Drills

For use on NC and CNC machines where high productivityand accurate holes are required in Cast Iron.


Cotter Pin Drills

For heavy duty drilling using a tang drive sleeve.

Tin Tip Jobber Drill

For higher performance in general purpose drilling.

Subland Drills

For drilling stepped holes in one operation.

Left Hand Jobber Drills

General purpose drilling in the left hand direction.

UDS Jobber Drills

For use on CNC where high productivity and accurate holesare required.


DRILL NOMENCLATURETANG

SHANKLENGTH

BODYLENGTH

FLUTELENGTH

DIAMETER

RECESS

OVERALLLENGTH

HELIXANGLE

MORSE TAPERSHANK


LIPCLEARANCEANGLE

BODYCLEARANCEDIAMETER

FLANK POINTANGLE

CHISELANGLE

WEBTHICKNESS

CIRCULARLAND

CHISELEDGE

LIPLENGTH

HEEL

DETAILED VIEW OF LIP CLEARANCE

POINT

TYPES OF SPIRAL (OR HELIX) ANGLES

20°

30°

40°

SLOW SPIRAL

NORMAL SPIRAL

QUICK SPIRAL


Standard Point

This point is suitable for general purpose drilling.

Split Point

The split point minimises end thrust and is self centering.

Long Point

Used for wood, plastic, hard rubber, fibres etc.

Cast Iron Point ("DX" Point)

The secondary angle reduces wear on the outer corners.

118°

125° - 135°

90°

125° - 135°

140° - 145°

118°

125° - 135°

70°

DRILL POINT STYLES


Heavy Duty Notched Point

The notched point reduces end thrust and optimises centrecutting efficiency with chisel strength. It is recommended forhard and high strength materials.

Web Thinned Point

The web thinned point reduces end thrust and improves centrecutting efficiency.

"UX" Point

The 130° special notched "UX" point style provides self centering,easier penetration, improved hole accuracy and improved loaddistribution. This special notch geometry gives a corrected rakeangle of 15° which provides strong point for harder materials,as well as preventing snatching with materials such asAluminium, Brass, Bronze and Plastics. Available on UDL andUDS drills.

125° - 135°

125° - 135°

125° - 135°

118°

135°

130° 10% D


Part Split Point

The 130° part split point is similar to the conventional split point.The part split point has a wider chisel edge. Provides easypenetration, self centering and optimises centre cutting efficiencywith chisel strength.

130°

140° - 145°

Benefits of the Parabolic Flute FormHeavy web construction increases rigidity under torsional loadthus eliminating chatter at the cutting edges which cause edgebreak down and early failure. The Parabolic drill web is 50-90%thicker than the standard drill, depending on drill diameter.

Wider flute form, together with quicker spiral, promotes betterchip removal while allowing easier coolant flow to the drill point.

• Conventional Web • Parabolic Flute Form• Thicker Web

• Chipbreaker

FLUTE FORMS


DIFFERENCE IN RELATIVELIP HEIGHT WILL DRILL ANOVERSIZE HOLE.

UNEVEN WEBTHINNING

WEB THINNINGTOO GREAT

LIPS UNEQUAL LENGTH(DIFFERENCE IN RELATIVE LIPHEIGHT.)

LIPCLEARANCEANGLETOO GREAT

LIPCLEARANCEANGLETOO SMALL

CHISEL ANGLETOO GREAT

CHISEL ANGLETOO SMALL

COMMON RE-SHARPENING ERRORS


STANDARD MORSE TAPER SHANK

To ISO 296 DIN 228 BS 1660

d b

R

e

D

a LL1

D1 d1

No.of

Taper

Fittingline

DiameterD

Diameterd

OverallLength

MaxL

D1 a MaxL1

Maxe

H13b

Maxd1

Taper /mm

on Dia

MaxR

123456

12.06517.78023.82531.26744.39963.348

9.014.019.025.036.052.0

65.580.099.0124.0156.0218.0

12.218.024.131.644.763.8

3.55.05.06.56.58.0

62.075.094.0117.5149.5210.0

13.516.020.024.029.040.0

5.26.37.911.915.919.0

8.713.518.524.535.751.0

5.06.07.08.010.013.0

0.049980.049950.050200.051940.052630.05214

Web thinning is recommended for:

1. restoring chisel edge to the original length after severalregrinds.

2. larger drills where the machine thrust is limited.3. difficult materials.

Lip Clearance Angle

Drill Size (mm) Angle (°)

Up to 33.1 - 66.1 - 1212.1 - 20Above 20

18-2414-1810-14 8-12 6-10


Multiple Diameter Drills

Specify whether drill is to be Step or Subland Type.D = Diameter of large, fluted section.P = Diameter of small, fluted section.A = Shank Diameter.L = Overall Length.F = Flute Length.E = Length of Small Diameter. This is measured from the extreme point to the bottom corner of the step angle.X°= Included angle of the step angle.S = Shank Length.

It is possible to drill two or more diameters in a hole onone operation with a correctly designed drill and theseare often used in mass production engineering.

Some of the hole types that can be drilled in a singleoperation.

If you have any cutting tool problem, please feel freeto contact our technical sales representatives.

D

E S

L

F

AP

X°

HOW TO ORDER SPECIALS


Modified Standards

There are many instances when a special tool (a tool not foundin the Somta catalogue or price list) can be manfactured from astandard product. We call this a ‘modified standard’.

Somta has both the capability and capacity to offer this servicewhich, under normal circumstances, means a short deliverytime.

The following are typical drill modifications:

Intermediate DiametersStandard sizes can be ground down to special diameters andtolerances.

Reduced Overall LengthsStandard drills can be cut to special lengths.

Drill PointsThe standard drill point angle is 118° included. This can be modifiedto any angle required. Many special points are available whichinclude web thinning, notch points, split points, double anglepoints, spur and brad points etc.

Tangs and FlatsTangs can be produced to DIN, ASA and ISO, also special whistlenotch flats on shanks.

Step DrillsStandard drills can be modified into step drills. (See drawing onpage 18).

Surface TreatmentsA full range of surface treatments including nitriding, streamoxide, chemical blackening, gold oxide and various PVD coatingsare available.


When an intermediate diameter or a non standard length of drillis required, the following diameters and lengths need to bespecified.

Straight Shank Drills

D = Drill DiameterA = Shank DiameterL = Overall LengthF = Flute LengthS = Shank Length


D = Drill DiameterL = Overall LengthF = Flute LengthM = Morse Taper Size

F

S

L

AD

F

L

D

M


CUTTING DIAMETER TOLERANCE

SOMTA Twist Drills are manufactured to h8 tolerance.2 Flute Drills

Cutting Diameter Tolerance on Twist Drills

Drill Diameter (mm) Diameter Tolerance (mm) Above Up to Plus Minus - 3 + 0 -0,014 3 6 + 0 -0,018 6 10 + 0 -0,022 10 18 + 0 -0,027 18 30 + 0 -0,033 30 50 + 0 -0,039 50 80 + 0 -0,046

Back Taper on Diameter of Fluted PortionThe drill diameter is normally reduced over the fluted portion toprevent jamming. The amount of back taper is a maximum of:0,08 mm on diameter per 100 mm length.

Back taper is usually only applied to sizes over 6 mm.


CORE DRILLING

Core Drill Nomenclature

OVERALL LENGTH

BODY

FLUTE LENGTH

RECESS SHANK

DIA

ME

TE

R

HELIXANGLE

LAND


3 FLUTES

WEBLAND

4 FLUTES


LIP CLEARANCEANGLE

CHAMFERLENGTH

LIPLENGTH


Cutting Diameter Tolerance on Core Drills

Core Drill Diameter (mm) Diameter Tolerance (mm) Above Up to Plus Minus - 6 + 0 - 0,018 6 10 + 0 - 0,022 10 18 + 0 - 0,027 18 30 + 0 - 0,033 30 50 + 0 - 0,039

A Guide to Core Drilling

Core drills are only used for enlarging diameters of existingholes whether drilled, punched or cored. Having no point, thedrill is only able to cut on the chamfer. The maximum amount ofmaterial that can be removed is restricted by the chamfer rootdiameter to 60% of the core drill diameter.

Because of its multi-flute construction the core drill gives betterhole size and surface finish than a two flute drill. Two flute drillsshould not be used to enlarge existing holes as they will tend tochip and break.

Speed and Feed rates for Core Drills

Speed - As for 2 flute drills

Feed - 3 Flute 1 to 1,5 x 2 flute drill feed rate

4 Flute 1,5 to 2 x 2 flute drill feed rate


OVERALL LENGTH

FLUTELENGTH

PILOTLENGTH

60°118°

60° 120°

TYPE 'B'

TYPE 'R'

RADIUS

PILOTDIAMETER

BODY DIAMETER

TYPE 'A'

CENTRE DRILLS

Centre Drill Nomenclature


Selecting the correct Centre Drill

TYPE "A"

For general centering operations on workpieces requiringadditional maching between centres.

TYPE "B" (Protected Centre), sometimes called Bell Type

The 60° cone surface produced by this centre drill is recessedbelow the surface of the workpiece and is therefore protectedfrom damage.

TYPE "R" (Radius)

The type "R" centre drill is also used for general centeringoperations, but produces a radius centre suitable for a varietyof male centre angles eg. 60°, 82° or 120° can be used as analternative to type "A" above.


The correct use of Centre Drills

A guide to successful drilling

Recommended SpeedsThe peripheral speeds for centre drills are the same as for 2flute drills given on page 34-35. For calculation purposes thenominal diameter given below should be used.

Centre Drill Nominal Centre Drill Nominal Size Diameter (mm) Size (mm) Diameter (mm)

BS 1 2 1 2 BS 2 3 1.25 2 BS 3 4 1.6 3 BS 4 6 2 4 BS 5 8 2.5 5 BS 6 11 3.15 6 BS 7 14 4 7

5 9 6.3 11 8 14 10 18

Recommended FeedsUse the nominal diameter given above to establish the feed asgiven on page 32-33, and then reduce by 40% for centre drills.

Re-sharpening of Centre DrillsCentre Drill can be re-sharpened on the point only. Refer to there-sharpening guide for 2 flute drill on page 16-17.


THE CORRECT USE OF DRILLS

A guide to successful drilling

• Make sure the workpiece is securely held and supported.Should it bend or move, it could cause the drill to break.

• Use a good socket and thoroughly clean both the socketand the taper shank of the drill. Do not use steel objects toseat the drill.

• Straight shank drill chucks must be able to hold the drillsecurely.

• Keep the drill sharp. Do not allow it to become blunt as itwill require extra-grinding to get it sharp again.

• Direct an adequate supply of the recommended coolant tothe point of the drill. (see page 34-35).

• Do not allow chips to clog the drill flutes.• When re-sharpening take care to achieve the correct point

geometry (see page 13-15) and do not overheat the drillwhen grinding.

• Use core drills for enlarging existing holes - 2 flute drillsare not designed for this purpose.

• Use the correct drill to suit the application (see page 5-10).

Deep Hole Drilling

A general guide

A hole deeper than 3 times its diameter is considered a “deephole”. Deep holes are successfully drilled by reducing speedand feed rates, as shown in the table on page 28. Care must betaken not to clog the flutes with chips.

In very deep holes it may be necessary to withdraw the drillfrequently to clear the flutes. Extra length drills should be usedwith a guide bush as close to the workpiece as possible tosupport the drill.


Depth of Hole % SpeedReduction

Depth of Hole % FeedReduction

Recommended Speeds for Deep Holes

3 x Drill Diameter 10% 4 x Drill Diameter 20% 5 x Drill Diameter 30% More than 6 x Drill Diameter 40%

Recommended Feeds for Deep Holes

3 to 4 x Drill Diameter 10% 5 to 8 x Drill Diameter 20%

Extra Length "Deep Hole" Drills (UDL Form)The SOMTA "Deep Hole" drill has a specially shaped flute form,commonly known as Parabolic, which gives rigidity for deephole drilling and improves chip flow, enabling the full depth ofthe hole to be drilled without withdrawal.

These drills are of special robust design for use on toughermaterials such as steels and cast irons with hardness up to1000 N/mm². Similar drills for softer materials such as aluminium,mild steel etc. with hardness up to 500 N/mm² are available onspecial request.

Coolant Feed DrillsHigher production rates can be achieved when deep hole drillingby using coolant feed drills.Harmful heat generation at the drill point is prevented by thesupply of coolant to the cutting face. This allows higher speedsand feeds and improved chip flow, thus eliminating the need toclear the flutes by withdrawal.


DRILLING PROBLEMS: CAUSES AND SOLUTIONS

Broken or Twisted Tangs(a) Possible Cause

Bad fit between the drill sleeve and the shank of the drill.Solution(i) Use only sleeves which are in good condition

(avoid worn or damaged sleeves).(ii) Ensure the drill shank and sleeve are thoroughly

clean.

Note:The tang is not intended to transmit the drive - it is only used forejection. The Morse Taper is self-holding and relies on a good fitin the sleeve to transmit the drive.

Drill Web Split(a) Possible Cause

The feed is too great.SolutionUse the correct feed for the drill size material - see page 32-33.

(b) Possible CauseInsufficient lip clearance behind the cutting edge.SolutionCheck that the lip clearance is as per information on page16-17.

(c) Possible CauseExcessive web thinning.SolutionThe web thickness should not be less than 10% of thedrill diameter.

(d) Possible CauseUsing a hard object to seat the drill in the sleeve.SolutionUse soft material e.g. copper or wood, to seat the drill.


Chipped or Broken Lips(a) Possible Cause

This is usually caused by excessive lip clearance anglesbehind the cutting edge.SolutionCheck that the lip clearance is as per information on page16-17.

Broken outer Corners(a) Possible Cause

Drilling thin material particularly when not properly supported.SolutionUse a sheet metal drill and clamp the workpiece securely.

(b) Possible CauseUsing a 2 flute drill to enlarge the diameter of an existinghole.SolutionOnly core drills should be used for this purpose.

Oversized and Out of Round Holes(a) Possible Cause

Unequal point angles.SolutionThis usually results when hand grinding the point. Use apoint grinding fixture or machine.

(b) Possible CauseUnequal cutting edge length (lip height).SolutionWhen re-grinding ensure that the same amount of materialis removed from both flanks.

(c) Possible CauseLoose spindle or worn drill sleeve.SolutionUse equipment which is in good condition.

(d) Possible CauseThe workpiece moves.SolutionThe workpiece must be securely clamped.


Cracks in cutting edges(a) Possible Cause

The point is overheated and cooled too quickly when re-sharpening.SolutionUse coolant when grinding or grind in stages, quenchingfrequently in soluble oil.

Worn outer Corners(a) Possible Cause

The peripheral speed is too high for the material beingdrilled.SolutionUse the recommended speed - see page 34-35.

Drill rubbing and not cutting(a) Possible Cause

Too little lip clearance behind the cutting edge.SolutionCheck that the lip clearance is as per information on page16-17.

Drill breaks at flute runout(a) Possible Cause

The workpiece moves during drilling.SolutionThe workpiece must be securely clamped.

(b) Possible CauseThe flutes are clogged with swarf.SolutionClear the flutes by frequently withdrawing the drill, or use adrill more suited to the material e.g. a UDL drill for aluminium.

(c) Possible CauseUsing the wrong type of drill e.g. using a jobber drill for thinmaterial.SolutionSee pages 5-10 for the correct drill to suit the application.


When setting to drill material of unknown machinability the slowestspeed and lightest feed should be used and these should begradually increased until optimum output per regrind is obtained.

Rough hole finish(a) Possible Cause

The drill is blunt.SolutionRe-sharpen as per information on page 16-17.

(b) Possible CauseInadequate supply of coolant to the point.SolutionThe coolant must reach the point of the drill.


DRILL FEED CURVE CHART

General Drilling Feeds (mm per revolution)

DrillDiameter

Range (mm)

FeedRange

DrillDiameter

Range (mm)

FeedRange

1 - 33 - 55 - 88 - 12

12 - 16

0.03 to 0.0750.05 to 0.180.10 to 0.280.15 to 0.350.20 to 0.45

16 - 2020 - 2525 - 3030 - 40Over 40

0.25 to 0.530.28 to 0.560.30 to 0.600.35 to 0.680.40 to 0.75


Drill Feeds (mm / rev.)

FE

ED

/ R

EV

(m

m)

DRILL DIAMETER (mm)

How to use the Drill Feed Chart

1. Locate Feed Curve (as given in the application data pages 35 & 37) on the right hand side of the drill feed chart.2. Locate Drill Diameter along bottom axis of chart.3. Determine point of intersection of Feed Curve and Drill Diameter.4. Project horizontally from point of intersection to left hand side of chart and read off nearest FEED / REV (mm).5. Select nearest feed on drilling machine within ± 20% of chart figure.


WORKPIECE MATERIAL

TYPE GRADE

CARBONSTEEL

&

ALLOYSTEEL

TYPICAL PHYSICALPROPERTIES

CODE TYPE

FREE CUTTING

0.3 to 0.4% Carbon

0.3 to 0.4% Carbon

0.4 to 0.7% Carbon

0.4 to 0.7% Carbon

HARDNESSBRINELL

(MAX)

TONS PERSQ.INCH

(MAX)

N / mm²(MAX)

STAINLESSSTEEL

HEATRESISTING

ALLOYS

TITANIUM

CASTIRONS

150

170

248

206

286

35

40

59

47

67

540

620

910

720

1030

Low Alloy Tool Steels

High Alloy Tool Steels

Heat Treatable Steels

Die Steels

248

330

380

59

75

87

910

1150

1300

Martensitic

(400 Series)248

Austenitic (Work

Hardening)

(300 Series)

300

54

65

810

1000

Inconell, Hastelloy

Nimonic Alloys350 78 1200

Commercially Pure

Commercially Alloyed

275

350

65

78

1000

1200

Grey Irons

Nodular Irons

Malleable Irons

110 - 300 - -

MANGANESESTEEL

ALUMINIUM

MAGNESIUMALLOYS

COPPERALLOYS

PLASTICS

AS SUPPLIED

Wrought Alloys

Cast Alloys

Silicon Alloys

Moderately

Machineable Alloys

LEADED COPPER ALLOYSFREE CUTTING BRASS

MEDIUM TO HIGH LEADED BRASS

LOW TO HIGH SILICON BRONZEMANGANESE BRONZE

ALUMINIUM SILICON BRONZE

COMMERCIAL BRONZE 90%PHOSPHOR BRONZE 5 - 10%

ALUMINIUM BRONZE

SoftHardReinforced

Free Cutting Alloys

Difficult to MachineAlloys

DRILL TECHNICAL DATA

AS SUPPLIED

AS SUPPLIED

141 - 142

147 - 148

151 - 152

153 - 163

STUBDRILLS

JOBBERDRILLS

101 - 102

105

154 - 164

155 - 161

167 - 177

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

155

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE

155

AS ABOVE156

AS ABOVE

156

AS ABOVE

AS ABOVE

AS ABOVE

AS ABOVE156


LONGSERIES

SPEEDMETRES /

MINCOOLANT

SOLUBLE OIL

OR

SEMI-

SYNTHETIC

OIL

25 - 30

15 - 20

10 - 15

15 - 24

10 - 15

4 - 8

12 - 16

6

5 - 10

15 - 25

7 - 11

25 - 35

15 - 30

25 - 30

4 - 6

Up to 45

30 - 35

40 - 100

40 - 50

30 - 36

15 - 20

25 - 30

< 20

FEEDCURVESee Page

32-33

H

F

H

H

C

E

F

C

K

C

L

L

M

L

-

SOLUBLE OIL

SOLUBLE OILEXTREME

PRESSURE

SOLUBLE OILEXTREME

PRESSUREOR

SULPHO-CHLORINATED

SOLUBLE OILEXTREME PRESSURE

ORSULPHO-CHLORINATED

SOLUBLE OILSULPHO-CHLORINATED

EXTREME PRESSURECHLORINATED OIL

DRY ORDETERGENT

WATER - SOLUBLEEMULSION

DRY OR

NEAT E.P. OIL

SOLUBLE OIL

(1 : 25)

LOW VISCOSITY

MINERAL OIL

SOLUBLE OIL

(1 : 20)

SOLUBLE OIL(1 : 20)

LIGHT MINERALOIL

DRY OR

SOLUBLE OIL

DRILL TECHNICAL DATA (cont.)

EXTRALENGTH

MORSETAPER

STANDARD

MORSETAPER

E/LENGTH

CODE TYPE DENOTES RECOMMENDED

116 - 117

109 - 110

118 - 119

120 - 121

122 - 123

124 - 125

126

201 - 202

203 - 204

205 - 206

208

241 - 242

244 - 245

251 - 252

254 - 255

AS ABOVE AS ABOVEAS ABOVE

261279

AS ABOVE


261279

AS ABOVE


261279

AS ABOVE

AS ABOVE AS ABOVE AS ABOVE AS ABOVE


261279

AS ABOVE




8501200

1200

850

850

1000

500

7001000

350

250

250

300

150

250350

UD DRILL TECHNICAL DATA

Free Cutting steels

Structural steel. Case carburizing steel

Plain carbon steel

Alloy steel

Alloy steel. Hardened and tempered steel


Free machining Stainless steel

Austenit ic

Ferritic + Austenitic, Ferritic, Martensitic

Lamellar graphite

Lamellar graphite

Nodular graphite, Malleable Cast Iron


Titanium, unalloyed

Titanium, alloyed

Titanium alloyed

Nickel, unalloyed

Nickel, alloyed

Nickel, alloyed

Copper

Beta Brass, Bronze

Alpha Brass

High strength Bronze

Al, Mg, unalloyed

Al alloyed Si < 0.5%

Al alloyed, Si > 0.5% < 10%

Al alloyed, Si > 10%, Al-alloys, Mg-alloys

Thermoplastics

Thermosetting plastics

Reinforced plastic materials

MATERIAL TYPESHARDNESS

HB

TENSILESTRENGTH

N/mm²

Ste

elS

tain

less

Ste

elC

ast I

ron

Tit

aniu

mN

icke

lC

op

per

Alu

min

ium

Mag

nes

ium

Syn

thet

icM

ater

ials

120

200

250

250

150300

200

200300

200

270

270350

150

270

270350

100

200

200

470

100

150

120

120

-

-

-

400

700

850

850

5001000

700

9001200

500

900

9001200

350

700

700

1500

350

500

400

400

-

-

-

700

900


SURFACE SPEEDMETRES

PER MINUTE

FEEDCURVE

see Page 32-33

DRILL TYPE &SURFACE

TREATMENT

NORMALCHIPFORM

extra long

middle/long

long

long

long

long

middle

long

long

extra short

extra short

middle/short

middle/short

extra long

middle/short

middle/short

extra long

long

long

extra long

middle/short

long

short

extra long

middle

middle/short

short

extra long

short

extra short UDCTiN

15 - 2020 - 30

JL

UDLTiNUDLTiNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDL

TiN TiCN TiAlNUDC

TiAlNUDC

TiAlNUDC

TiAlNUDC

TiAlNUDLTiCNUDSTiCNUDSTiCNUDL

TiCN TiAlNUDL

TiCN TiAlNUDL

TiCN TiAlNUDLTiNUDSTiNUDLTiNUDSTiNUDLTiNUDLTiNUDSTiNUDSTiNUDLTiNUDSTiN

35 - 4550 - 7025 - 3540 - 5025 - 3035 - 4025 - 3035 - 4015 - 2025 - 3015 - 2020 - 2518 - 2127 - 328 - 10

12 - 1510 - 1516 - 2230 - 3545 - 5525 - 3035 - 4518 - 2125 - 3512 - 1722 - 2620 - 2530 - 3513 - 1720 - 25

5 - 67 - 11

12 - 1620 - 25

6 - 810 - 12

5 - 610 - 1255 - 6580 - 9560 - 70

90 - 10530 - 4045 - 5027 - 3340 - 5075 - 85

110 - 12565 - 75

100 - 11555 - 65

80 - 10027 - 3340 - 5075 - 85

110 - 12555 - 65

80 - 100

HJHJGIGIEGEGEG

KMEGGIGIEGEGEGEGCEGIGICELNLNLNKMNNNNLNKMLNJL

UD DRILL TECHNICAL DATA (cont.)


SOLID CARBIDE DRILLS TECHNICAL DATA

HardnessHB

Material TypeGrade

SteelFree cutting steelsStructural steelPlain carbon steelAlloy steelAlloy steel, hardened & tempered steel

Stainless SteelFree machiningAustenit icFerritic & martensitic

Cast IronLamellar graphiteLamellar graphiteNodular graphite, Malleable cast ironNodular graphite, Malleable cast iron

TitaniumUnalloyedAlloyedAlloyed

NickelUnalloyedAlloyedAlloyed

CopperCopperBeta brass, bronzeAlpha brassHigh strength bronze

Aluminium AlloysWrought alloysCast alloys < 5% SiCast alloys > 5% Si < 10% SiCast alloys >10% Si

SyntheticsDuroplastics (short chipping)Thermoplastics (long chipping)Fibre reinforced synthetics

1201201209050

756040

90759075

503020

553520

50505040

1501207545

100100100

Recommended SurfaceSpeed in m/min for

Coated TungstenCarbide Drills

< 120< 200< 250< 350> 350

< 250< 250< 300

< 150< 300< 200< 300

< 200< 270< 350

< 150< 270< 350

< 100< 200< 200< 470

< 100< 150< 120< 120

---

min max

< 400< 700< 850

< 1200> 1200

< 850< 850

< 1000

< 500< 1000< 700

< 1000

< 700< 900

< 1200

< 500< 900

< 1200

< 350< 700< 700

< 1500

< 350< 500< 400< 400

---

TensileStrength

N/mm2

15015015012070

907550

15090

15090

604030

705030

80707050

2001509060

300300300

TO CALCULATE:RPM = (surface speed x 1000) / (π x d)FEED RATE in mm/min = rpm x feed per revoloution

NOTE: For uncoated drills reduce surface speed by 35% to 50%.For drill depths deeper then 3xD suggest peck drilling.


Recommended feed in mm per revolutionfor Coated Tungsten Carbide Drills

Drill Diameter in mm

0.030.030.030.020.02

0.020.020.02

0.030.020.030.02

0.020.020.02

0.020.020.02

0.030.020.020.02

0.030.030.030.03

0.040.040.04

1

0.050.050.050.040.04

0.040.030.04

0.050.040.050.04

0.040.040.03

0.040.040.03

0.050.040.040.04

0.060.060.060.06

0.070.080.07

2

0.080.080.080.060.05

0.050.050.05

0.080.060.080.06

0.060.060.05

0.060.060.05

0.080.060.060.06

0.090.090.090.09

0.110.120.11

3

0.300.300.300.240.18

0.220.190.22

0.300.240.300.24

0.240.240.18

0.240.240.19

0.300.240.240.24

0.360.360.360.36

0.420.480.42

12

0.100.100.100.080.06

0.070.070.07

0.100.080.100.08

0.080.080.06

0.080.080.07

0.100.080.080.08

0.120.120.120.12

0.140.160.14

4

0.130.130.130.100.08

0.090.080.09

0.130.100.130.10

0.100.100.08

0.100.100.08

0.130.100.100.10

0.150.150.150.15

0.180.200.18

5

0.250.250.250.200.15

0.180.160.18

0.250.200.250.20

0.200.200.15

0.200.200.16

0.250.200.200.20

0.300.300.300.30

0.350.400.35

10

0.200.200.200.160.12

0.140.130.14

0.200.160.200.16

0.160.160.12

0.160.160.13

0.200.160.160.16

0.240.240.240.24

0.280.320.28

8

0.150.150.150.120.09

0.110.100.11

0.150.120.150.12

0.120.120.09

0.120.120.10

0.150.120.120.12

0.180.180.180.18

0.210.240.21

6

0.330.330.330.260.20

0.230.210.23

0.330.260.330.26

0.260.260.20

0.260.260.21

0.330.260.260.26

0.390.390.390.39

0.460.520.46

13

0.350.350.350.280.21

0.250.220.25

0.350.280.350.28

0.280.280.21

0.280.280.22

0.350.280.280.28

0.420.420.420.42

0.490.560.49

14

0.400.400.400.320.24

0.290.260.29

0.400.320.400.32

0.320.320.24

0.320.320.26

0.400.320.320.32

0.480.480.480.48

0.480.640.48

16

SOLID CARBIDE DRILLS TECHNICAL DATA (cont.)

% feed reduction for deep hole drilling

Hole Depth % reduction

3 x drill diameter4 x drill diameter5 x drill diameter

> 6 x drill diameter

10%20%30%40%


SELECTING THE CORRECT REAMER, COUNTERSINK &COUNTERBORE

Standard Reamers, Countersinks & CounterboresThe following are available ex-stock from Somta.

Parallel Shank Countersinks

MTS Countersinks

To produce a countersink suitable for countersunk head screws,also used as a deburring tool.

Parallel Shank Counterbores

MTS Counterbores

For counterboring holes to suit capscrew heads.

Parallel Hand Reamers

General hand reaming.

MTS Parallel Machine Reamers

General machine reaming.

REAMERS, COUNTERSINKS & COUNTERBORES


MTS Taper Bridge Machine Reamers

For opening out existing holes for alignment on structuralsteel work.

MTS Machine Chucking Reamers


Parallel Shank Machine Chucking Reamers


Hand Taper Pin Reamers

For reaming holes to suit standard taper pins.

SpecialsReamers for specific Applications.

MTS Taper Socket Finishing Reamers

Finishing of Morse Taper holes.

MTS Taper Socket Roughing Reamers

Rough reaming of Morse Taper holes.

Straight Flute

Spiral Flute


REAMERS

Reamer Nomenclature

SECTION A-A

NO CIRCULARLAND

BEVEL LEADANGLE

TAPER LEAD

BB

AA

TAPER LEADANGLE

SHANK

SQUARE

SIZE OFSQUARE

DIA

ME

TE

R

OVERALL LENGTH

CUTTING LENGTH RECESS SHANK

B

B

DIA

ME

TE

R

PRIMARYCLEARANCEANGLE

CLEARANCEANGLE

CIRCULARLAND

SECTION B-B

CIRCULARLAND

CLEARANCEANGLE

FLUTE

CENTRE HOLE

RADIAL FACECUTTING EDGE

FRONT END VIEW OF PARALLELMACHINE REAMER

MORSE TAPER


The correct use of Reamers

A guide to successful reaming• Make sure the workpiece is securely held and supported.

Should it bend or move, it could result in a poor finish orcause the reamer to break.

• Use a good morse taper sleeve and thoroughly clean boththe sleeve and the taper shank of the reamer.

• As a reamer only cuts on the bevel lead and not on theperipheral land, it is essential to keep it sharp. A bluntreamer wears on the outer corners on the bevel lead,resulting in a poor fininsh, undersize holes andincreased torque. (See page 44-45 for re-sharpeningdetails.)

• Direct an adequate supply of the recommended lubricantto the cutting area. When reaming high tensile materials,an improved surface finish can be achieved by usingchlorinated or sulphurised oils.

Stock RemovalReamers are used to produce accurate holes with a goodsurface finish. It is a common fault to leave too little stock forremoval by reaming. This results in a rubbing action andexcessive wear of the reamer. The table below shows approxi-mate amounts of stock to be removed by reaming.

Machine Reamers

Above

1.5361325

Up to1.536

1325

Pre-Drilled(mm)

Pre-CoreDrilled(mm)

0.30.30.30.40.50.5

0.20.20.20.250.30.3

Size of ReamedHole (mm)


Reamer DiameterRange (mm)

Feed (mm/rev)

Above

1.536

1325

Up to1.536

1324

Light (L)0.005 - 0.0250.025 - 0.05

0.05 - 0.10.1 - 0.15

0.15 - 0.250.25 - 0.5

Medium (M)0.012 - 0.05

0.05 - 0.10.1 - 0.150.15 - 0.250.25 - 0.5

0.5 - 1

Heavy (H)0.025 - 0.0750.075 - 0.150.15 - 0.250.25 - 0.380.38 - 0.760.76 - 1.27

TolerancesSomta reamers are manufactured to produce holes to H7tolerance. The tolerance limits shown in the table below areadded to the nominal reamer diameter.eg. nominal diameter = 12mm actual diameter = 12.008mm/12.015mm

Tolerance limits for reamers and hole sizes produced.

Reamer DiameterRange (mm)

Cutting DiameterTolerance

Above136101830

Up to3610183050

mm+0.004 +0.008+0.005 +0.010+0.006 +0.012+0.008 +0.015+0.009 +0.017+0.012 +0.021

mm0 +0.0100 +0.0120 +0.0150 +0.0180 +0.0210 +0.025

Hole DiameterTolerance H7

Other useful tolerances can be found on page 147.

Hand ReamersThe hand reaming allowance should be approximately twothirds of the machine reaming allowance.

* Feed Conversion Table

Re-Sharpening ReamersA reamer is only sharpened on the bevel lead which performsthe cutting action. This operation must be done only by skilled


SHANK DIAMETER

SHANK

LENGTH

PILOT

PILOT DIAMETER

RECESS

BODY

BODY DIAMETER

COUNTERBORES

Counterbore Nomenclature

operators on appropriate machine tools. When re-sharpening itis essential to maintain both the original relief angle of 6°- 8° andthe concentricity of the bevel lead.


The correct use of Counterbores

A General GuideCounterbores are used to create seatings for cap screw headsand are therefore identified by the cap screw they suit. Theyare available with straight or Morse Taper shanks.

Cap Screw Pilot Drill Counterbore Size Size (mm) Diameter (mm) M 3 3.4 6 M 3.5 3.9 6.5 M 4 4.5 8 M 5 5.5 10 M 6 6.6 11 M 8 9 15 M 10 11 18 M 12 14 20

Speeds & FeedsThe speeds and feeds for counterbores are approximately 80%to 85% of those for drills as given on page 34-35.The counterbore diameter given in the above table is used forthis calculation.

Re-Sharpening CounterboresCounterbores are re-sharpened only by grinding the front cuttingedges, maintaining the original relief angle of 6°- 8°.


The correct use of Countersinks

A General GuideCountersinks are normally used to produce a 60° or 90° chamferrecess which accommodates the corresponding 60° or 90°screw head. They are available in straight or Morse Taper Shank.

Speeds and FeedsThe speeds and feeds for countersinks are the same as thosefor drills (see page 34-35) and are based on the diameter midwaybetween the largest and smallest diameter of the countersink.

Re-Sharpening CountersinksThe axial relief is critical to the performance of the countersinkand should not be altered. When re-sharpening, grind only theflute face.

OVERALL LENGTH

CUTTINGANGLE

BODYDIAMETER

MINIMUM CUTTINGDIAMETER

BODY DIAMETER

CUTTINGANGLE

MINIMUM CUTTINGDIAMETER

BODY DIAMETER

OVERALL LENGTH

COUNTERSINKS

Countersink Nomenclature


REAMING PROBLEMS: CAUSES AND SOLUTIONS

Poor Surface Finish(a) Possible Cause

Incorrect speed and/or feed.SolutionUse the recommended speed/feed - see page 50-51.

(b) Possible CauseA Worn reamerSolutionDo not allow the reamer to become too blunt. See page 44-45 for re-sharpening details.

(c) Possible CauseInsufficient or wrong type of lubricant.SolutionApply an adequate supply of the correct lubricant to thecutting area. See the drill table on page 34-35 for therecommended lubricants.

(d) Possible CauseDamaged cutting edges.SolutionUse a reamer which is in good condition.

Reamer Chattering(a) Possible Cause

Lack of rigidity in set up.SolutionOnly use equipment which is in good condition and makesure the workpiece is securely held.

(b) Possible CauseFeed too low.SolutionUse the recommended speed/feed - see page 50-51.

Reamer showing rapid wear(a) Possible Cause

Too little stock in the hole for reaming causing the reamerto rub and not cut.


Solutionsee page 43 for recommended stock removal.

(b) Possible CauseSpeed too high or feed too low.SolutionUse the recommended speed/feed - see page 50-51.

(c) Possible CauseThe workpiece material is too hard.SolutionUse a HSS-Co reamer.

Tapered or Bell-Mouthed holes(a) Possible Cause

Mis-alignment of the reamer and the hole.SolutionAlign the reamer and the hole.

(b) Possible CauseThe machine spindle and/or bearings are worn.SolutionOnly use equipment which is in good condition.

Reamer rubbing and not cutting(a) Possible Cause

Too little reaming allowance in the hole.SolutionSee table of stock removal on page 43.

(b) Possible CauseReamer re-sharpened with too little or no relief on thebevel lead.SolutionRe-grind the bevel lead to a 6°- 8° relief.

Oversized holes(a) Possible Cause

Excessive run-out on the machine spindle or holdingdevice eg. taper sleeve, collet or chuck.SolutionOnly use equipment which is in good conditon.


†Speedm/min

*Typeof

FeedTYPE GRADE

CARBONSTEEL

&

ALLOYSTEEL

FREE CUTTING

0.3 to 0.4% Carbon

0.3 to 0.4% Carbon

0.4 to 0.7% Carbon

0.4 to 0.7% Carbon

HARDNESS

BRINELL

TONS PER SQIN. (MAX)

N/mm²(MAX)

150

170

248

206

286

35

40

59

47

67

525

600

900

700

1000

248

330

380

59

75

87

900

1125

1300

STAINLESSSTEEL

MartensiticFree Cutting

MartensiticStd. Grade

AusteniticFree Cutting

Austenitic Std. Grade

12-15

7-10

5-8

M-H

M

L

7-10

5-8

2-4

5-8

2-5

M

L-M

5-8

2-5

L-M

L-M

As Supplied

380 54 810

TITANIUM

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Alloyed

Titanium Alloyed

NIMONICALLOYS

Wrought

Cast

300

350

67

78

1000

12002-5 L

170

200

275

340

380

40

43

65

76

85

600

650

975

1140

1275

7-10 M

2-4 L-M

TOOLSTEEL

HSS Standard

Grades

HSS Cobalt Grades

Hot Working Steel

Cold Working Steel

225

225

48

54

720

800

7-10 M

REAMER TECHNICAL DATA

† See Speed Conversion Chart on page 148-149.* See table on page 44.

M

M

L



REAMER TECHNICAL DATA (cont.)

† See Speed Conversion Chart on page 148-149.* See table on page 44.

†Speedm/min

*Typeof

FeedTYPE GRADE

CASTIRONS

Grey

Ductile

Maleable

Hardened & Tempered

HARDNESS

BRINELL

N/mm²(MAX)

MANGANESESTEEL

250

330

52

74

780

1100

As Supplied

COPPERALLOYS

12-15

10-13

12-15

4-5

2-3

20-35

30-45

15-30

10-15

15-45

7-15

H

H

H

M

M-H

M

As Supplied

Brass Free Cutting

Brass Low Leaded

Bronze Silicon

Bronze Manganese

CopperBronze AluminiumBronze CommercialBronze Phospor

12-15 M-HPLASTICS

Soft

Hard

Reinforced

M-H

M-H

M-H

M

L

ALUMINIUMALLOYS

As Supplied 30-45 H

MANGANESEALLOYS

As Supplied 35-60 H

ZINCALLOYS

As Supplied 30-45 H

As Supplied


TONS PER SQIN. (MAX)


SELECTING THE CORRECT TAP

Short Hand Taps

For general purpose hand or machine use for short productionruns. Best suited for materials which do not present chip disposalproblems.

This regular type is the basic tap designed as a general purposetool for hand and machine operation.

As this basic tap will give acceptable performance in mostmaterials and for short production runs, it is usually the mosteconomical tap to use. However, it performs best in materialswhere the cutting action results in chips which break up readilyand do not present problems of chip disposal.

The regular hand tap has four flutes in sizes larger than 1/4 inchdiameter. These taps may not be suitable because of inadequatechip space when deep or blind holes have to be tapped in softstringy materials. This applies particularly to the coarser pitchthreads such as BSW and UNC.

If a gun tap or spiral fluted tap cannot be used, a three fluted tapwhich permits extra chip space, is recommended.

TAPS

Taper

Second

Bottoming


Rougher

Intermediate

Finisher

Left Hand Short Hand Taps

For general purpose hand or machine use for short productionruns. Best suited for materials which do not present chip disposalproblems.

Serial Hand Taps

Serial taps comprise of one or more undersized roughing tapswhich remove most of the material before final sizing with afinishing tap.

Some reasons for using serial taps are:

(a) The toughness of the material being tapped.(b) The amount of material to be removed could cause

swarf choking with a single tap.(c) The very small tolerance on pitch diameter.(d) An extremely good finish required.

For general purpose machine or hand use in tough materials,producing accurate threads with a high finish. Used in sequenceto remove most of the material in stages before finally sizingwith the finishing tap.



Spiral Flute Short Machine Taps

Mainly for work in blind holes and on ductile materials, such asaluminium and zinc alloys, which produce long stringy chips.The taps have a 15° or 35° right hand helix. The flute shapeeliminates clogging and jamming, resulting in improved tap life.

These taps are designed primarliy for machine tapping of blindholes, are used to the best advantage in materials which producelong stringy chips. The shearing action provided by the spiralflutes produces a better finish on difficult to machine metals andcauses the chips to be drawn back, eliminating clogging at thecutting chamfer.

Gun Nose (Spiral Point) Short Machine Taps

For machine use on through holes. Suitable for a wide range ofmaterials. The gun nose creates chip disposal ahead of the tapwhile the flute geometry allows an adequate supply of lubricantto the cutting area, making higher tapping speed possible.

Gun nose taps have straight flutes supplemented by angularcutting faces at the point. These faces cut with a shearingaction which propels the chips ahead of the tap leaving theflutes clear for the free flow of coolant to the point.

Primarily designed for use in through holes, these taps can beused in blind holes providing that there is ample clearancebeyond the threaded section to accomodate the chips. Theadvantages of a gun nose tap are, the shearing action of theangular cutting faces which produce a fine finish on the threadsand, shallower flutes which permit a stronger cross sectionthroughout the tap.

15° Spiral Flute

35° Spiral Flute


Pipe Taps

For machine use on pipe work for parallel threads.

For machine use on pipe work for tapered threads.

Pipe taps are supplied with PARALLEL threads or with TAPERthreads. These taps are shorter than a similar size of regularhand tap, but the design features are the same. They are suitablefor hand or machine use.

Colour Band Application (CBA) Taps

The primary benefit of the CBA range is enhanced threadingperformance due to geometry designed for specific materialapplication groups. The result is an improved quality of finishand an increased number of holes per tap, giving extended taplife and reduced cost per hole. Manufactured from HSSE-V3steel (High Vanadium) for greater wear resistance.


Yellow Band

Designed for more ductile materials such as Aluminium,Magnesium Alloys, Soft Brass (MS58), Plastics, Zinc Alloys andCopper. Used to tap materials with hardness up to 200HB, tensilestrength up to 700N/mm².

Wide flutes allow more efficient swarf removal which preventsclogging and excessive torque. High rake angle improves shearcharacteristic and reduces build-up on the cutting edge, allowingtap to cut more freely for longer periods. Spiral flute taps have40° right hand helix, allowing ductile material swarf to beefficiently forced out of the hole. The yellow band tap is suppliedas standard in bright condition.

Green Band

The machinebility of different steels is just as varied as theirproperties. Soft-tough construction steels place completelydifferent demands on the tools, and the green band combinationof taps has been perfected for this range of steels.

Green Band characteristics include ability to machine materialswith hardness up to 250HB, tensile strength up to 900N/mm².Surface finish - TiN Coating (standard) increases surface hard-ness of the tool to around 85RC, with excellent resistance toabrasion and cold welding. Thread and flute configuration designfor free cutting and structural steels in the general purposerange of medium tensile strengths.

Gun Nose

Spiral Flute

15° Spiral Flute

35° Spiral Flute

Gun Nose


Yellow Band Fluteless Taps

For machine use on through or blind holes. Best suited forductile materials, such as aluminium and zinc alloys as thethreads are cold formed, not cut like a conventional tap. Forslightly tougher materials fluteless taps in the range of 5mm to12mm can be supplied with a gash.

These taps are designed for machine tapping in ductile materials,“Fluteless” taps have no flutes or cutting faces, but have specialroll forming lobes with circular lands and have long or shorttaper leads for through or blind holes.

Red Band

Designed for high tensile materials such as Tool Steels, HeatTreatable Steels, Spring Steel, Case Hardening Steel, UnalloyedTitanium, Nitriding Steel, Cold Drawn Constructional Steel andHigh Tensile Steel.

Used to tap materials with hardness up to 470HB, tensile strengthup to 1500N/mm². Spiral flute taps have 15° right hand helixwhich efficiently forces high tensile material swarf up out ofthe hole, while still maintaining correct cutting geometry. The redband tap is supplied as standard with TiAlN coating.

White Band

Designed for highly abrasive materials such as Cast Iron andreinforced plastics. Used to tap materials with hardness up to300HB, tensile strength up to 1000N/mm². Increased number offlutes reduces torque and increases tap life. Taps have 15°right hand helix. The white band tap is TiAlN coated as standard.

Gun Nose

Spiral Flute

Spiral Flute


Blue Band

Designed for tough materials, such as Stainless Steel, TitaniumAlloys, Cast Steel, Heat Resisting Steel and Work HardeningSteel. Used to tap materials with hardness up to 350HB, tensilestrength up to 1250N/mm².

Truncated thread after lead reduces frictional contact with thethreaded hole and allows easier penetration of coolant. Spiralflute taps have 40° right hand helix allowing tough material swarfto be efficiently removed from the hole. Supplied as standardwith TiAIN coating.

Special taps are available on request.

Spiral Flute

Gun Nose


TAP NOMENCLATURE

SIZE OF SQUAREACROSS FLATS

SECTION B-B

BB

FLA

T L

EN

GT

H

AA

n

LEADANGLE

NOMINALDIAMETER

ROOTDIAMETER

TH

RE

AD

LE

NG

TH

CH

AM

FE

R L

EA

D

n = No. OF THREADSPER INCH.

p = PITCH

LAND

FLUTE CUTTINGFACE

WEBTHICKNESS

SECTION A-A

SHANKDIAMETER

p

OV

ER

ALL

LE

NG

TH


Abbreviations for standard thread forms

BSW - British Standard WhitworthBSF - British Standard FineBA - British AssociationBSB - British Standard Brass

General Specifications: ISO 529Threads ground to: BS 949: 1976 CLASS 2

BSP - British Standard Pipe (Fine) "G" SeriesBSPT - British Standard Pipe Taper (Rc Series)

General Specifications: ISO 2284Threads ground to: BS 949: 1976 G-Series

NPS - National Pipe StraightNPT - National Pipe Taper

General Specifications: ANSI 94.9 1979Threads ground to: ANSI 94.9 1979

UNC - Unified National CoarseUNF - Unified National Fine

General Specifications: ISO 529Threads ground to: ANSI B1.1 1982 2B

M - MetricM F - Metric Fine

General Specifications: ISO 529 ISO 2283 (Long Series)Threads ground to: ISO 2857 - 1973, Class 2

General Specifications: DIN 371 / DIN 374 / DIN 376Threads ground to: DIN 802 CLASS 6H

U N E F - Unified Extra Fine


In some countries the name “PLUG” is commonly used to indicatea Bottoming tap. In America it is used to indicate a second tap. Toavoid confusion with American terms, the terminology adoptedby British Standard 949 1979 as shown above, should be used.

STANDARD LEAD (CHAMFER ANGLES)

TAPER

SECOND

BOTTOMING

6 to 8 threads

3.1/2 to 5 threads

2 to 3 threads

4°

8°

23°

Short Hand and Machine, Long Shank 4° (6-8 threads) TaperMachine and Pipe Taps 8° (3.1/2-5 threads) Second

23° (2-3 threads) Bottoming

Spiral Point Taps 8° (4-5 threads)

Spiral Flute Taps 23° (2-3 threads)

Fluteless Taps 23° (2-3 threads)


NUT

MAJOR DIA.

PITCH DIA.

MINOR DIA.

THREADANGLE

HELIX ANGLEAT PITCH DIA.

PITCH

SCREW

THREAD FORMS

COMPONENT ELEMENTS


WHITWORTH

H = 0.866Ph = 0.61343Pr = 0.1443P

ISO METRIC

60°

p

H hr

r

55°

p

H = 0.960491Ph = 0.640327Pr = 0.137329P

H h


UNIFIED

H = 0.86603P5/8H = 0.54127P

1/4H = 0.21651P1/8H = 0.10825P

BA

H = 1.1363365Ph = 0.6Ps = 0.26817Pr = 0.18083P

1/4H

p

1/8H60°

5/8H

p

s47-½°

H

s

h

r

H


H = 0.960237Ph = 0.640327Pr = 0.137278P

BSPT

d = MAJOR DIAMETER AT GAUGE PLANEd1 = MINOR DIAMETER AT GAUGE PLANETAPER = 1 IN 16 ON DIAMETER

BSB

H = 0.86603Ph = 0.5237Pr = 0.1667P

55°

P

90°d1

H hr

d

P

55°

rhH


H = 0.866Ph = 0.8Pf = 0.033P

H = 0.866Ph = 0.8Pf = 0.033P

NPT

d = MAJOR DIAMETER AT GAUGE PLANEd1 = MINOR DIAMETER AT GAUGE PLANETAPER = 1 IN 16 ON DIAMETER

Pf

NPS

f

hH

60°

P

90°d1

f

60°f

H hd


ACME

h = 0.5P + CLEARANCEF = 0.3707PFc = 0.3707P - (0.256 x MAJOR DIAMETER ALLOWANCE)

TRAPEZOIDAL

h = 0.5P + CLEARANCE

Fc

29°

F P

h

30°

h

1/2P

P


RECOMMENDED TAPPING DRILL SIZES

Size0.40.450.50.60.70.750.811

1.251.251.51.51.75

22

2.52.52.533

3.53.53.544

4.54.555

5.5

TappingDrill Size (mm)

*Fluteless Tapping Drill Sizes

M2M2.5M3M3.5M4M4.5M5M6M7M8M9M10M11M12M14M16M18M20M22M24M27M30M32M33M36M39M42M45M48M52M56

1.6 (1.8)*2.05

2.5 (2.75)*2.9 (3.2)*3.3 (3.65)*3.7 (4.1)*4.2 (4.6)*5 (5.5)*

66.8 (7.4)*

7.88.5 (9.25)*

9.510.2 (11.1)*

1214

15.517.519.52124

26.528.529.53235

37.540.54347

50.5

Metric Coarse

Pitch

(For 75% thread depth)


Metric FineSize

TappingDrill Size (mm)

MF2MF2.5MF3MF3.5MF4MF4.5MF5MF6MF7MF8MF8MF9MF10MF10MF12MF12MF14MF14MF16MF16MF18MF18MF20MF20MF22MF22MF24MF24MF25MF25MF27MF30MF30MF32MF33MF36

0.250.350.350.350.50.50.5

0.750.750.75

111

1.251.251.5

1.251.51

1.51.52

1.52

1.52

1.52

1.522

1.52

1.51.51.5

1.752.152.653.153.54

4.55.256.257.2789

8.7510.7510.5

12.7512.515

14.516.516

18.518

20.520

22.522

23.52325

28.528

30.531.534.5

Pitch


Metric Fine (cont)

MF36MF39MF40MF42MF45MF48MF50MF52

2.01.51.51.51.51.51.51.5

3437.538.540.543.546.548.550.5

3/321/85/323/167/321/45/163/87/161/29/165/83/47/81"1.1/81.1/41.1/21.3/42"

48403224242018161412121110987765

4.1/2

1.92.553.23.74.55.16.58

9.310.512.213.516.519.5222528343945

SizeTapping

Drill Size (mm)Pitch

BSWNominalDiameter

TappingDrill Size (mm)TPI



3/167/321/45/163/87/161/29/165/83/47/81"1.1/81.1/41.1/2

322826222018161614121110998

44.75.46.88.39.811

12.714

16.519.522.525.529

34.5

No.3No.4No.5No.6No.8No.10No.121/45/163/87/161/29/165/83/4

484040323224242018161413121110

22.252.6

2.753.43.84.45.16.68

9.410.812.213.516.5

BSFNominalDiameter


UNCNominalDiameter



No.3No.4No.5No.6No.8No.10No.123/161/45/163/87/161/29/165/83/47/81"1.1/81.1/41.3/81.1/2

56484440363228322824242020181816141212121212

2.12.352.652.93.54.14.64

5.56.98.59.811.512.814.517.520.523.526.529.532.536

UNC (cont)NominalDiameter


19.522252831343945

9877665

4.1/2

7/81"1.1/81.1/41.3/81.1/21.3/42"

UNFNominalDiameter



BANominalDiameter


012345678910

25.428.231.334.838.343.147.952.959.165.172.6

5.14.53.93.43

2.652.3

2.051.8

1.551.4

NPS

NominalDiameter


1/81/43/81/23/41"1.1/41.1/22"

2718181414

11.1/211.1/211.1/211.1/2

9.112

15.519

24.530.539.445.557.5

1/81/43/81/23/4

2718181414

8.411

14.2517.523

NPTNominalDiameter



1/81/43/81/25/83/47/81"1.1/41.1/21.3/42"

281919141414141111111111

8.811.815.51921

24.528.53140

45.551.557

BSP

NominalDiameter


BSPTNominalDiameter


281919141411111111

8.611.515.018.524.0

30.2539.045.056.5

1/81/43/81/23/41"1.1/41.1/22"

1"1.1/41.1/22"

11.1/211.1/211.1/211.1/2

2937.543.555.5

NPT (cont.)NominalDiameter



FLUTELESS TAPS

Fluteless taps are used for cold forming threads in ductilematerials and have the following advantages.

(a) Increased strength and tap life resulting from:(i) Elimination of flutes which reduce the shear strength

of the tap.(ii) The lack of cutting edges which, in a conventional

tap, wear and break down.(iii) The lack of chips, which sometimes causes jamming.

(b) Better blind hole tapping due to the lack of chips and problemsrelating to chip removal.

(c) Higher productivity due to faster tapping speeds.(d) Stronger threads.

The grain fibres of the metal are not cut, but displaced, to formthe threads, which are stronger than cut threads. It is acceptedthat a 60% cold formed thread is as strong as a 75% cut thread.

STRONGER THREAD

GRAIN FIBRE OFMETAL UNBROKENBURNISHED THREAD

NO CHIPS


CORRECT USE OF TAPS

A guide to successful machine tapping• Use the correct tap to suit the application (see page 52-58).• Select the correct tapping drill size (see page 68-74).• Direct an adequate supply of the recommended lubricant

to the cutting area of the tap (see page 88-91).• Make sure the workpiece is securely held.• Use a tapping attachment suited to the application and

align the tap with the hole.• When using a machine without lead screw feed, hand

feed the tap until sufficient engagement produces selffeed.

• When using a machine with lead screw feed, set thelead to correspond with that of the tap. This also applieson two and multi start taps.

Preparation of HolesA good hole is a pre-requisite of a good thread. Some of thefactors which contribute to inferior threads are:(a) Out of round holes. The thread will be correspondingly out

of round.(b) Poor surface finish in the hole.(c) Size of the hole. A hole which is too small will cause

overloading of the tap with the possible breakage.(d) Hard spots and abrasive surfaces in the cored holes.

These holes should be pre-drilled.

Percentage Thread DepthFor general purpose work a thread depth of 75% is recommen-ded. A drill size equal to the minor diameter of the tap producesa 100% thread depth. This practice is normally recommendedfor the following reasons.(a) 100% thread depth requires excessive power to turn the

tap, with consequent possible breakage.(b) 100% thread depth is only 5% stronger than the normal

depth of 75%.(c) Even a 50% thread depth still produces a thread stronger

than its mating bolt.


1/2PITCH

WIDTH OFFLAT CREST

CRESTRAD.

MIN

OR

DIA

.

EF

FE

CT

IVE

DIA

.

MA

JOR

DIA

.TR

IAN

GU

LAR

HE

IGH

T

NUT

BOLT

CRESTRAD.

BASIC DEPTHOF THREAD

WIDTH OFFLAT ROOT

ROOTRAD.

MIN

OR

DIA

.

EF

FE

CT

IVE

DIA

.

MA

JOR

DIA

.

1/2PITCH

PITCH

Basic sizes and tolerance classes

To allow for clearance between mating internal and externalthreads, taps are manufactured with oversize allowances addedto the basic diameters.These basic diameters plus the oversize allowances establish:

(a) the minimum effective diameter; and

(b) the minimum major diameter.

ROOTRAD.

THREADANGLE


Limits of Tolerance

Effective Diameter - The tolerance is the amount of variationallowed in the manufacture of the tap. This tolerance is addedto the minimum effective diameter to establish the maximumeffective diameter.

It follows that:Basic Effective + Oversize

= Minimum Effective

Basic Effective + Oversize + tolerance= Maximum Effective

The effective diameter can only be measured with special tapmeasuring equipment.

Major Diameter - The minimum major diameter is established byadding the oversize allowance to the basic major diameter (thenominal thread size). Therefore, on measurement, the majordiameter of the tap is larger than the nominal thread size, andmust not be used to judge the size of the tap.

The maximum major diameter of the tap is governed by thethread form and is therefore not subject to a tolerance.


Tap Tolerance Classes

Relationships of Tap Classes to Nut Tolerances

Metric Threads

Unified Threads

6G(MAX)5G(MAX)

4G(MAX)

MINIMUM'G' GRADES

NUTS8H(MAX)

7H(MAX)6H(MAX)

5H(MAX)4H(MAX)

MIN.'H' GRADES

BASICPITCH DIAMETER

12345123451234512345

TO

LER

AN

CE

BA

ND

12345123451234512345

1234123412341234

CLA

SS

1

CLA

SS

2

CLA

SS

3

TO

LER

AN

CE

BA

ND

NUTS1B(MAX)

2B(MAX)

3B(MAX)

MINIMUM ALL NUT CLASSES BASICPITCH DIAMETER

1234512345123451234512345

1234512345123451234512345123451234512345

12345123451234512345123451234512345

CLA

SS

1

CLA

SS

2 CLA

SS

3


Class 1 TapThis is closest to basic, having little oversize allowance, and isnormally specified for "close" fit threads, eg. Unified 3B, Metric4H, 5H.

Class 2 TapThis is normally specified for "medium" fit threads, eg. Unified2B, Metric 6H, 4G, 5G.

Class 3 TapThis is futhermost above basic size and used for "free" fitthreads, eg. Unified 1B, Metric 7H, 8H, 6G.

Under favourable working conditions, the following threadtolerances should be produced by the new class taps.

All Somta HSS taps are supplied to Class 2, 6H unless otherwisespecified.

RE-SHARPENING TAPSMaximum productivity and tap life can only be obtained from atap that is kept in good condition and handled with care.

When re-sharpening becomes necessary, regrinding by handis not recommended, though it is probably better than usingchipped or worn taps. The recommended method is to usespecial tap grinding attachments or machines, and to follow theoriginal form of the tap.

MetricUnifiedWhitworth FormBA

Class 14H, 5H3BClose ClassClose Class

Class 26H, 4G, 5G2BMedium ClassMedium Class

Class 37H, 8H, 6G1BFree ClassFree Class


TAPPING PROBLEMS: CAUSES AND SOLUTIONS

Damaged tap threads in the hole(a) Possible Cause

Mis-alignment of the tap with the hole before starting to tap.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(b) Possible CauseThe tap is too dullSolutionUse a tap which is in good condition.

(c) Possible CauseWork hardened skin in the drilled hole.SolutionWork hardening can be avoided when drilling by using thecorrect speeds,and coolants. See page 34-35. Use serialtaps.

(d) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 52-58.

Poor finish of the thread(a) Possible Cause

Using the incorrect tap.SolutionUse the recommended tap.

(b) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 68-74.

(c) Possible CauseThe tap is too dull.SolutionUse a tap which is good condition.

(d) Possible CauseInsufficient number of threads on the lead.


SolutionUse a tap with the correct lead.

(e) Possible CauseMis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(f) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 52-58.

Torn threads in the tapped hole(a) Possible Cause

The flutes are clogged by chips.SolutionUse a spiral point or a spiral flute tap.

(b) Possible CauseDistortion of the walls in a thin walled workpiece.SolutionUse a multi-fluted tap.

(c) Possible CauseThe threads on the tap are broken.SolutionUse a tap which is in good condition.

(d) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the cutting area. See page 88-91.

(e) Possible CauseUsing the incorrect or unsuitable tap for the material.SolutionUse the recommended tap for the material. See page 52-58.

(f) Possible CauseTap hitting the bottom of the hole.SolutionAllow sufficient clearance at the bottom of the hole.


(g) Possible CauseIncorrect rake angle.SolutionUse the recommended tap for the material. See page 52-58.

Excessive Tap Wear(a) Possible Cause

Mis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(b) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the cutting area.

(c) Possible CauseThe material is abrasive.Solution(i) Use the correct type of tap.(ii) Use a surface treated tap.

(d) Possible CauseUsing the incorrect tap.Solution(i) Use a tap with the correct lead.(ii) Use a surface treated tap.

(e) Possible CauseIncorrect rake angleSolutionUse the recommended tap for the material. See page 52-58.

Over-Heating of tap(a) Possible Cause

Lack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the cutting area.

(b) Possible Cause


The tap is too dull.SolutionUse a tap which is in a good condition.

(c) Possible CauseThe wrong type of tap is used.SolutionUse the recommended tap. See page 52-58.

(d) Possible CauseExcessive tapping speed is applied.SolutionUse the recommended tapping speed. See page 88-91.

Bell-Mouthed Tapped Hole(a) Possible Cause

Mis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(b) Possible CauseThe workpiece is not rigidly held.SolutionSecure the workpiece

(c) Possible CauseExcessive pressure is applied when starting to tap.SolutionOnly sufficient pressure to initiate self-feeding should beapplied.

(d) Possible CauseInsufficient number of threads on the lead.SolutionUse a tap with a longer lead.

(e) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 68-74.

Over-size tapped hole(a) Possible Cause


Using the incorrect tap.SolutionUse the recommended tap. See page 52-58.

(b) Possible CauseMis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(c) Possible CauseLack of/or wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricant

to the cutting area.(d) Possible Cause

Incorrect rake angle.SolutionUse the recommended tap for the material. See page 52-58.

Tap binding in the hole(a) Possible Cause

Using the incorrect tap.SolutionUse the recommended tap.See page 52-58.

(b) Possible CauseThe drilled hole is too small.SolutionUse the recommended drill size. See page 68-74.

(c) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the cutting area. See page 88-91.

(d) Possible CauseThe flutes are clogged with chips.SolutionUse a spiral point or a spiral flute tap.

(e) Possible CauseIncorrect rake angle.


SolutionUse the recommended tap for the material. See page 52-58.

Flutes clogged with chips(a) Possible Cause

Using the incorrect tap.SolutionUse a spiral point or spiral flute tap.

(b) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the cutting area.

Tap Breakage(a) Possible Cause

Using the incorrect tap.SolutionUse the recommended tap. See page 52-58.

(b) Possible CauseThe tap is too dull.SolutionUse a tap which is in good condition.

(c) Possible CauseThe drilled hole is too small.SolutionUse the recommended tapping drill size. See page 68-74.

(d) Possible CauseThe drilled hole is too shallow.SolutionAllow clearance at the bottom of the hole when drilling.

(e) Possible CauseMis-alignment of the tap and the hole.SolutionCare must be taken to align the tap with the hole beforestarting to tap.

(f) Possible CauseThe flutes are clogged with chips.


SolutionUse a spiral point or spiral flute tap.

(g) Possible CauseExcessive tapping speed is applied.SolutionUse the recommended tapping speed. See page 88-91.

(h) Possible CauseThe tap holding device is not suitable.SolutionUse the appropriate tapping attachment.

(i) Possible CauseThe work material is work hardened.SolutionUse serial taps.

(j) Possible CauseLack of/or the wrong type of lubricant.SolutionApply an adequate supply and the correct type of lubricantto the chamfer lead of the tap.

(k) Possible CauseIncorrect rake angle.SolutionUse the recommended tap for the material. See page 52-58.


TYPE GRADE

CARBONSTEEL

FREE CUTTING

0.3 to 0.4% Carbon

0.3 to 0.4% Carbon

0.4 to 0.7% Carbon

0.4 to 0.7% Carbon

HARDNESS

BRINELL

TONS PER

SQ IN.N/mm²

ALLOYSTEEL

150

170

248

206

286

33

38

54

44

63

500

570

800

650

950

248

330

380

54

74

82

810

1100

1250

STAINLESSSTEEL

Martensitic Free CuttingMartensitic Std. GradeAustenitic Free CuttingAustenitic Std. Grade


As Supplied

248 54 810

TITANIUM

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Alloyed

Titanium Alloyed

NIMONICALLOYS

Wrought

Cast

300

350

67

78

1000

1170

170

200

275

340

380

38

43

65

76

85

570

650

975

1140

1275

TOOL STEEL

HSS Standard

Grades

HSS Cobalt Grades

Hot Working Steel

Cold Working Steel

225

225

48

54

720

810

MANGANESESTEEL

As Supplied

Tough

Hard

TAP TECHNICAL DATA


*TAPPERIPHERAL

SPEEDm/min

THROUGHHOLE

RECOMMENDEDTAP TYPE

BLINDHOLE

ALTERNATIVETAP TYPE

THROUGHHOLE

BLINDHOLE

LUBRICANTS

Sp/Point Sp/Flute Str/Flute Str/Flute

8-10

8-12

10-15

Sulphur

based oil

Sp/Point Sp/Flute Str/Flute Str/Flute 8-12Sulphur

based oil

Sp/Point Sp/Flute Str/Flute Str/Flute 2-6

Heavy duty

Sulphur

based oil

See CBA Tap section pages 92-93. 2-4Chlorinated

oil

2-4Chlorinated

oil

Sp/Point Sp/Flute Str/Flute Str/Flute 8-10Sulphur

based oil

Sp/Point Str/Flute Str/Flute - 15-20Sulphur

based oil

TAP TECHNICAL DATA (cont.)

See CBA Tap section pages 92-93.

* Tapping speeds for fluteless taps are 2-3 times higher than the recommended speeds given.


TYPE GRADE HARDNESS

BRINELL

TONS PER

SQ IN.N/mm²

ALUMINIUMALLOYS

240

330

52

74

780

1110

COPPERALLOYS

Brass Free Cutting

Brass Low Lead

Bronze Silicon

Bronze Manganese

Copper Free Machining

Copper Electrolytic

Bronze Aluminium

Bronze Commercial

Bronze Phosphor


As Supplied

PLASTICS


CASTIRONS

Grey

Ductile

Maleable

Hardened & Tempered

Long ChipShort Chip

As Supplied

MANGANESEALLOYS

As Supplied

ZINCALLOYS

As Supplied

Soft

HardReinforced

As Supplied


*TAPPERIPHERAL

SPEEDm/min

THROUGHHOLE

RECOMMENDEDTAP TYPE

* Tapping speeds for fluteless taps are 2-3 times higher than the recommended speeds given.

BLINDHOLE

ALTERNATIVETAP TYPE

THROUGHHOLE

BLINDHOLE

LUBRICANTS

Str/Flute Str/Flute Sp/Point -

4 -8

5-10

Dry soluble oilor paraffin

Fluteless Fluteless Sp/Point Sp/Flute20-25

10-15

Sol. oil orlight material

oil

Sol. oil orlight mineral oil

Chlorinatedoil or soluble oil

Sp/Point Sp/Flute Str/Flute Str/Flute 15-20 Sul. B Oil

Fluteless Fluteless Str/Flute Str/Flute 15-20 Soluble Oil

Fluteless

Sp/Point

Fluteless

Sp/Point

Fluteless

Str/Flute

Fluteless

Str/Flute

Str/Flute

Str/Flute

Sp/Point

Str/Flute

Str/Flute

Str/Flute

Sp/Point

Str/Flute

15-20

25-30

10-12

3-5

15-20

8-12

10-12

3-5

3-5Sol. oil or

light mineral oil

Str/Flute Str/Flute Sp/Point - Dry4-7

12-15



CBA TAP TECHNICAL DATA

MATERIAL TYPES HARDNESSHB

TENSILESTRENGTH

N/mm²

Ste

elS

tain

less

Ste

elC

ast I

ron

Tita

nium

Nic

kel

Cop

per

Alu

min

ium

Mag

nesi

umS

ynth

etic

Mat

eria

ls

120

200

250

250

250350

350

250

250

300

150

150300

200

200300

200

270

270350

150

270

270350

100

200

200

470

100

150

120

120

400

700

850

850

8501200

1200

850

850

1000

500

5001000

700

7001000

700

900

9001200

500

900

9001200

350

700

700

1500

350

500

400

400

-

-

-

Surface Treatment (Coating) TiN, TiCN, TiAIN coatings are available on request

Free Cutting steels

Structural steel. Case carburizing steel

Plain carbon steel

Alloy steel

Alloy steel.Hardened and tempered steel


Free machining Stainless steel

Austenit ic

Ferritic + Austenitic, Ferritic, Martensitic

Lamellar graphite

Lamellar graphite


Nodular graphiteMalleable Cast Iron

Titanium, unalloyed

Titanium, alloyed

Titanium alloyed

Nickel, unalloyed

Nickel, alloyed

Nickel, alloyed

Copper

Beta Brass, Bronze

Alpha Brass

High strength Bronze

Al, Mg, unalloyed

Al alloyed Si < 0.5%

Al alloyed, Si > 0.5%< 10%

Al alloyed, Si > 10%Al-alloys, Mg-alloys

Thermoplastics

Thermosetting plastics

Reinforced plastic materials

-

-

-


RECOMMENDED TAP TYPE

CBA TAP TECHNICAL DATA (cont.)

NORMALCHIPFORM

Recommended X SuitableSPEED M/Min

STANDARD COATEDWHITEBAND

YELLOWBAND

BLUEBAND

REDBAND

extra long

middle/long

long

long

long

middle

long

long

extra short

extra short

middle/short

extra long

middle/short

12

12

10

10

8

5

9

6

5

11

8

11

8

8

9

6

9

18 - 27

18 - 27

18 - 24

18 - 24

9 - 15

9 - 15

18 - 24

9 - 15

8 - 15

18 - 27

9 - 18

18 - 27

9 - 18

9 - 15

12 - 18

6 - 12

12 - 18

5

4

11

30

18

5

15

6 - 12

5 - 11

15 - 24

43 - 55

40 - 49

6 - 12

24 - 30

30

18

15

27

11

8

43 - 52

30 - 36

24 - 30

-

15 - 21

9 - 15

X

X

X

X

X

X

X

X

X

X

X

X

long

middle/short

middle/short

extra long

long

long

extra long

middle/short

long

short

extra long

middle

middle/short

short

extra long

short

extra short

GREENBAND

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X


2386212119091736152712731091955849764636546477425382347318294273239212191174159141127116106989185807368

Metres / Min 4 6 8 9 10 12

Tap Sizemm Inch1.61.82

2.22.53

3.54

4.556789

1011121314161820222427303336394245485256

1/16

3/32

1/8

5/32

3/161/4

9/325/16

3/8

1/2

9/165/8

3/47/81"

1.1/81.1/4

1.1/2

1.3/4

2"

8007086375795104253643182832552121821591421271161069891807164585347433935333028272423

1194106595586976463754647842538231927323921219117415914713611910696878071645853494642403734

1592141512741158101984972863756651042536431928325523221219618215914112711610694857771656157534946

17911598143313031147955819718637573477409358318286260238220205179159143130119106958780736864605551

1988176815911446127410619097967076375304553983543182892652452771991771591451331181069688827671666157

Revolutions per minute

TAP PERIPHERAL SPEED TO rpm CONVERSION CHART


15 18 21 25 27 30 36

298326522386216919091591136411931061955795682597531477434398367341298265239217199177159145133122114106999285

3579318228632603229119091636143212731146954818716637573521477441409358318286260239212191174159147186127119110102

41763712334130372673222719091671148513371113955835742668608557514477418371334304275245223203186171159149139129119

497144193977361631822651227319891768159113261136994885795723663612568497442398362331295265241221204189177166153142

5369477342953905343628642455214819091719143212271074955859781716661614537477430391353318286360239220205191179165153

59655303477343393818318227272387212219091592136411931061955868796734682597530477434398354318289265245227212199184170

7158636457275207458238183273286425462292190916361432129311461041955881818716636573521477424382347318294273255239220205

Revolutions per Minute

TAP PERIPHERAL SPEED TO rpm CONVERSION CHART (cont.)


CUTTERS

SHANK CUTTERS

Selecting the correct Shank Cutter

Two and Three Flute End Mills

Two and three flute end mills are shank type cutters withperipheral teeth and end teeth of the plunging type. Intended forgeneral purpose use, they have right hand cutting, right handhelical teeth; they are used on keyway and closed slottingoperations where the close minus tolerance of the cuttingdiameter allows slot widths to be produced in one pass.

These cutters are also extensively used when profiling andend milling aluminium alloys, due to the greater chip spacerequired by this material.

Two Flute Ball Nose End Mills

Ball nosed two flute end mills are manufactured to the sametolerances as the normal two flute end mill, and have a centrecutting ball end. They are used extensively in die making forcutting fillets, radiused slots, pocketing etc. These cutters haveright hand cutting, right hand helical teeth.



Multi-Flute End Mills

Multi-flute end mills are shank type cutters with peripheral teethand end teeth of the both plunging and non-plunging type.

Designed for general purpose use they have right hand cutting,right hand helical teeth, and are used in stepping and profilingapplications. They can also be used on slots where the plustolerance of the cutting diameter is not critical.

Roughing End Mills

Shank type cutters with right hand cutting, right hand helicalteeth on the periphery with roughing profile and with heavyduty end teeth.

These cutters are robust and durable even under heavy cuttingconditions on a wide range of materials. They are intended forrapid and heavy rates of stock removal where surface finish isof lesser importance. Available in coarse and fine pitch knuckleform and flat crest type.

Corner Rounding Cutters

Straight tooth cutters with right hand cutting teeth. Intended toproduce a true convex up to 90° of arc.


Woodruff Cutters

Shank type cutters with right hand cutting alternate helicalperipheral teeth. Available in a range of diameters and widths.Designed to produce slots to suit standard woodruff keys.

T-Slot Cutters

Shank type cutters with right hand cutting alternate helicalperipheral teeth as well as teeth on either face. Intended foropening out existing slots to form the T-slots used extensivelyon machine tables. They are produced in a range of diametersand widths to allow clearance on a standard range of bolt headsizes.

Dovetail Cutters

These angle cutters have right hand cutting straight teeth andnon-plunging end teeth. They are used wherever dovetails orangles are required and are available in a range of angles anddiameters.


Solid Carbide End Mills

Solid Carbide Tooling (Standard Range)

Somta’s Solid Carbide Tooling Range is a comprehensive familyof solid carbide stub and jobber length drills, 2 and 4 flute endmills and ball nose end mills, in both regular and long series, andalmost any special form carbide tooling.

Solid Carbide Roughing End Mills

A range of high performance roughing end mills for rapid stockremoval, with new geometry designed for very low cuttingforces. These new roughers are for general engineeringapplications such as side cutting, slotting and ramping and canbe used on machines with medium to low rigidity.

Solid Carbide Finishing End Mills

A range of high performance finishing end mills for operation onhard materials in the range 48 to 52 HRC (455-512HB). Thefinishers are designed for peripheral milling of contours andcomplex shapes, and are ideal for hardened mould and diesteels up to 52HRC (512HB).


Solid Carbide VariCut End Mill

Somta's new “Vari-Style” End Mill, VariCut has a new patentpending tool design. This unique design uses a new core formand a new reinforced end geometry with unequal flute spacingwhich enables it to remove the most amount of material in theleast amount of time with an excellent surface finish.OnStainless, or Titanium, it will match or outperform any other 4flute “Vari-Style” End Mill in the market.

Solid Carbide Hi-Feed-End Mill

Somta’s Hi-Feed end mill with patent pending geometry removesthe most amount of material in the least amount of time withextended tool life. It is excellent in 3 dimensional cutting of hardand super hard steels up to 62HRC (684HB).

Solid Carbide End Mills for Aluminium

Somta's high efficiency carbide end mill range with optimal flutegeometry provides all the required features for high performancemachining of aluminium, with the added benefits of greater stockremoval rates at high speeds and feeds, excellent surface finishquality and extended tool life.


Shank Cutter Nomenclature

SHANKDIAMETER

THREAD 20 T.P.I.WHITWORTHRIGHT HAND

RECESSDIAMETER

SIDETEETH

HELIXANGLE

CUTTER DIAMETER

CU

TT

ING

WID

TH

RE

CE

SS

LE

NG

TH

SH

AN

K L

EN

GT

H

OV

ER

ALL

LE

NG

TH

TH

RE

AD

LEN

GT

H


Dovetail Cutter

Tolerance js16 on cutting diameter(see page 147 for tolerance tables)

Inverted Dovetail Cutter

Tolerance js16 on cutting diameter(see page 147 for tolerance tables)

Corner Rounding Cutter

Tolerance H11 on radius and js14 on cutting tip(see page 147 for tolerance tables)

TYPES OF SHANK CUTTERS


T-Slot Cutter

Tolerance d11 on metric cutting diameter and widthTolerance h12 on fractional cutting diameter and width(see page 147 for tolerance tables)

Woodruff Cutter

Tolerance h11 on metric cutting diameter and e8 on width(see page 147 for tolerance tables)

Tolerance on fractional diameter issize +0,381

+0,127and on width issize +0,000

- 0,025



OVERALL LENGTH

CUTTINGLENGTH

CUTTINGDIAMETER

SHANKDIAMETER

ENDTEETH

HELIXANGLE

End Mills

AXIAL GASHANGLE

END TEETHPRIMARYCLEARANCE

END TEETHSECONDARYCLEARANCE

LAND

RADIALRAKE

PERIPHERALPRIMARYCLEARANCE

PERIPHERALSECONDARYCLEARANCE

END TEETHCONCAVITY

OVERCENTRETOOTH

GASHANGLE

END TEETHGASH


Two Flute End Mill

Tolerance e8 on cuttingdiameter (see page 147 fortolerance tables)

Two Flute Ball Nose End Mill


Three Flute End Mill


Multi-Flute End Mill

Tolerance k10 on cuttingdiameter (see page 147 fortolerance tables)

Roughing End Mill

Tolerance k12 on cuttingdiameter (see page 147 fortolerance tables)

TYPICAL END MILL OPTIONS

CENTRECUT

CENTREHOLE


Shank Options

Plain ShankTolerance h7 on metricshank diameter (see page147 for tolerance tables)

Threaded Shank

Tolerance h8 on metric/fractional shank diameter(see page 147 fortolerance tables)

Flatted Shank

Tolerance h6 on metricshank diameter (see page147 for tolerance tables)

THREADLENGTH

THREAD20 T.P.I.WHITWORTHFORM


Hints for successful Shank Cutter usage

It is assumed that the workpiece clamping and machine sizeand power are adequate for the intended operation. Alwaysselect the most suitable tool for the job on hand; a few minutesspent on selection can save hours of machining. Use roughingend mills when removing large amounts of stock; two or threeflute end mills for deep slotting applications, for edge cuttingand espically when machining light alloys. Use multi-flute endmills for edge cutting as well as for light finishing cuts.

Use threaded shank or flatted shank cutters where heavy stockremoval and high tooth loads are involved. Plain shank cuttersare particularly suitable for quick change CNC applications andfor pre-setting off the machine.

Where possible check workpiece condition and hardness. Checkchucks and collets regularly ensuring that they are in goodcondition. The most likely cause of cutter run-out is damagedchucks and collets. Always clean cutter shanks and colletsprior to assembly. Check that cutters are running true. Maintaincutters in a sharp condition to ensure maximum stock removal,surface finish and maximum power requirement.

Re-sharpen immediately when signs of wear are visible, sinceregrinding is then a relatively quick operation requiring little stockremoval and with resulting increase in tool life. (See page 125for resharpening details). Cutter storage is of paramountimportance due to the brittle nature of the hardened cuttingedges of all cutting tools. Poor storage often causes damagesuch as chipping of the cutting edges and breakage of corners,resulting in a tool which is useless. As in all machining operationscleaniless is essential.

The best machining results are produced by cutters operatingat the correct speed and feed to suit the material being worked.(See page 134-137 for technical data.)


ARBOR MOUNTED CUTTERS

Selecting the correct Arbor Mounted Cutter

Staggered Tooth Side and Face Cutters

As the name suggests, side and face cutters have teeth on theperiphery as well as on the sides. Designed with ruggedalternate helical teeth, these cutters offer optimum performancewhen used for deep slotting with rapid stock removal; the cuttingaction of the alternate helical teeth combined with the coarsepitched side teeth giving excellent qualities of smooth cutting,efficient stock removal and good surface finish.

Straight Tooth Side and Face Cutters

Intended for light cuts and shallow slotting operations, thestraight tooth side and face cutter is often used in a straddle


Cylindrical Cutters

Intended for medium/light surfacing cuts these helical cuttersoffer the benefits of shock reduction combined with a goodcutting action.

Angle Cutters

Produced with light duty straight teeth these cutters are usedmainly for cutting dovetails, serrations and angled slots on lessdifficult materials.

milling function where two parallel surfaces are machinedsimultaneously. It is considered to be a compromise tool due tothe reduced cutting action of its straight teeth, which causegreater shock when meeting the workpiece than cutters withhelical teeth.


Shell End Mills - Plain Form

With helical peripheral teeth these cutters fill the gap betweennormal shank cutters and the much larger facing cutters,thiscuttter is better suited to light/medium cuts in a facing or steppingoperation with its plain bore.

Shell End Mills - Roughing Form

As the name implies, these cutters with their helical teeth androughing profile are particularly efficient in areas where largevolumes of stock must be removed at high speed and wheretough materials are to be worked.


Arbor Mounted Cutter Nomenclature

Side and Face Cutter - (Staggered Tooth shown)

Tolerance js16 on metric cutting diameter and k11 on width(see page 147 for tolerance tables)

LAND

RAKEANGLE WIDTH

KEYWAY

PERIPHERALCLEARANCE

PERIPHERALTEETH

SIDE TEETH

HELIXANGLE

DIAMETER

SIDE TEETHCONCAVITY

BORE


OVERALLLENGTH

RAKEANGLE

HELIXANGLE

INTERNALDIAMETER

DIA

ME

TE

RShell End Mills - Plain Form

See page 110 for application.

Shell End Mills - Roughing Form

See page 110 for application.


Side and Face Cutter - Straight Tooth

Tolerance js16 on metric/fractional cutting diameter and k11 onmetric/fractional width(see page 147 for tolerance tables)

Cylindrical Cutter

Tolerance js16 on cutting diameter and width(see page 147 for tolerance tables)


Single Angle Cutter

Tolerance js16 on cutting diameter and js14 on width(see page 147 for tolerance tables)

Double Angle Cutter

Tolerance js16 on cutting diameter and width(see page 147 for tolerance tables)


Hints for successful Arbor Mounted Cutter Usage

Some of the many factors governing efficient use of bore cuttersare:-

1) Condition of machine2) Machine power available3) Machine capacity4) Nature of the workpiece

Attention should be given to these factors prior to commence-ment. When using arbor mounted cutters the following pointsshould be observed:-

Taper drive of arbor should be in good condition and fit correctlyinto machine drive.

Arbor and bushes should be kept in good and clean condition;dirty bushes cause run-out of cutters.

Arbors should be oiled and carefully stored when not in use;bent arbors are useless and expensive to replace.

Cutters should run true to prevent overloading of one or twoteeth and extensive regrinding later.

Fit the cutter as closely as possible to the machine column witha support as near to the cutter as the workpiece will allow.

Running bushes and support bearings should be kept clean andin good running condition, particularly with regard to the bushfaces. Lack of support will cause damage to the cutter and theworkpiece. Always use correct lubricants.

Workpiece clamping should be rigid and able to withstand theforces acting upon it under the action of the cutter.


Select correct speeds and feeds for the cutter in use and thenature of the workpiece material and the size of the cut to betaken.

Use recommended coolants and direct flow to the point ofcutting. Consult the coolant suppliers for specific recommen-dations. Adequate cooling is essential to prevent overheating ofthe cutter and failures associated with overheating.

Always use drive keys between the cutter and the arbor; frictionbetween the cutter and the arbor bushes is seldom sufficientwhen cutters are under correct load.

Never force a cutter onto a arbor or over an ill-fitted key. Protectyour hands by wrapping the cutter in a soft material whenfitting or removing it from the arbor.

Due to the brittle nature of hardened tool steels it is not advisableto “remove” a cutter with a mallet once it has been tightenedonto the arbor.

Maintain cutters in sharp condition. Regrind as soon as wearbecomes apparent.

Store cutters carefully when not in use, using a light film of oil toprevent rusting.

Cleanliness of cutters and arbors is essential.

Use helically fluted cutters wherever possible to minimise shockas teeth contact the workpiece.


SLITTING SAWS

Selecting the correct Slitting Saw

Slitting Saw - Plain

Intended for shallow cutting-off operations, these saws havestraight teeth on the periphery and are tapered on width towardsthe bore to prevent binding. They are available in either coarseor fine pitch to suit the type and section of materials to be cut.

Slitting Saws - Side Chip Clearance

Intended for optimum production of deep narrow slots and forsawing operations, these saws have alternate helical teeth onthe periphery combined with side teeth to ensure efficient stockremoval, clean cutting action, and good surface finish.


Slitting Saw Nomenclature

Slitting Saw - Plain


Slitting Saw - Side Chip Clearance



± 2 times depth of cut

Hints for successful Slitting Saw usage

It is recommended that side plates be used with slitting saws.


CLIMB OR CONVENTIONAL MILLING

From the very beginning of the milling process, it was foundpractical to always rotate the end mill in the opposite direction tothe feed of the workpiece. This is termed conventional milling.

In conventional milling the end mill engages the workpiece at thebottom of the cut. The end mill teeth slide along until sufficientpressure builds up to break through the surface of the work.This sliding action under pressure tends to abrade the periph-ery of the end mill with resulting dulling.

Also in horizontal conventional milling, the cutting action has atendency to lift the workpiece, fixture and table from their bear-ings. In recent years, milling machines have been greatly im-proved through backlash elimination and greater rigidity so thatclimb milling is now possible. Climb milling improves surfacefinish and increases tool life.

In climb milling the end mill rotates in the direction of the feed.The tooth meets the work at the top of the cut at the thickestportion of the chip. This provides instant engagement of the endmill with the workpiece producing a chip of definite thickness atthe start of the cut without the rubbing action resulting fromconventional milling. It further permits the gradual disengage-ment of the teeth and work so that feed marks are largelyeliminated.

Climb milling will often provide better product finish, permit greaterfeed per tooth and prolong the cutter life per sharpening. It isparticularly desirable to climb mill such materials as heat treatedalloy steels and non-free machining grades of stainless steelfor better tool life and to reduce work hardening. It is not recom-mended on material having a hard scale, such as cast or scalyforged surfaces, because abrasion would quickly ruin the cut-ting edges. Also some very soft steels do not lend themselvesto climb milling because of their tendency to drag and tear.


Climb milling cannot be applied to every milling operation andshould not be attempted if the material and the machine setupare not adapted to this type of milling.

Conventional MillingEngage cut thin

Climb MillingEngage cut thick

Feed

Feed

Force

Force


PROBLEM SOLVING

Milling problems are often caused by one or more of the follow-ing factors, which should be carefully checked in a systematicand logical manner.

Speeds and FeedsSee page 134-137 for recommendations.

CoolantsSeek advice from your supplier.

Cutter SelectionAlways select the correct type and quality of cutter to suit theapplication.

ArborsStraightness/runout/size/wear/damageBushing-wear/damage.

Re-sharpeningClearance angles. See page 125.RunoutBurning/overheatingSurface finish

Milling MachinesSlides and gib stripsLead screws and nutsBacklash eliminationAttachmentsDefective workheadsWorn tailstocksWorn centres



WorkholdingWorkholder conditionWorkholder suitabilityWorkholder alignmentWorkholder rigidity

Workpiece ConditionMachine suitabilityMaterial specificationsMaterial hardnessMaterial surface conditionsMachining characteristics

Cutter HoldersColletsChucksDraw barsRunoutDamage


DIFFICULT TO MACHINE MATERIALS

There are number of materials which are generally regarded asbeing difficult to machine. In general terms the material beingworked is considered to be difficult when it does not respondreadily to normal machining techniques. Among these “difficult’materials are aluminium alloys, stainless steel and work hard-ening steels.

Aluminium Alloys require relatively high speeds and feeds.They respond best to cutters with few teeth and correspond-ingly wide chip spaces, and can be worked very effectivelyby using two flute end mills, which have the advantage offewer teeth engaged in the cut. In many cases coolant maynot be needed to cool the cutter although it is of benefit inlubricating and particularly in removing chips. Climb milling givesdefinite advantages and shows significant benefits where agood quality surface finish is needed. These materials can beworked quite effectively with regular tooling, although ben-efits would be obtained from custom tools in the event of largevolume production being the norm.

Stainless Steels require lower speeds and higher feed ratesand often benefits are obtained from using corner radii andchamfers. These materials respond well to the conventionalcutting method but rigidity of machine and setup are critical.Light finishing cuts are to avoided but where necessary shouldbe taken at a feed rate as high as possible to meet with sur-face finishing requirements. It is crucial that these materials be“worked”, and “rubbing” of the cutter against the workpieceshould be avoided. Selection of speed and feed rates is ofgreat importance. Coolant must be used in large volume andbe directed at the cutting area. Benefits are often obtainedfrom a higer coolant concentration or from using cutting oils.

Work Hardening Steels such as some stainless and man-ganese steels can be successfully machined by using thesame techniques as described for stainless steels above.


RE-SHARPENING AND CARE OF MILLING CUTTERS

The productivity of a milling machine depends to a large degreeon the efficiency of the milling cutter. Best results in both pro-duction and cutter life are obtained by sharpening cutters cor-rectly and carefully, and by taking proper care in handling andstorage. A correctly sharpened cutter requires less driving power,produces better quality work and gives longer service than anincorrectly or hastily sharpened cutter.

The following factors should be considered:- Correct handling and storage to prevent damage.- Restoration of the cutting edges to their original geometry using correct procedures.- Suitable wheel selection to ensure correct surface finish and stock removal. Consult wheel suppliers for specific recommendations.

Remember that milling cutters are precision tools and must behandled carefully. Damage due to incorrect handling or storagecan be seen as a flaw upon the milled surface of a workpiece.Grinding should be needed only as a result of dulling due to use.Regrinding to remove damage caused by rough handling mustbe considered to be a wasted process which reduces the lifeof a cutter.

Correct clearance angles and radial rakes can be obtained fromdata given on page 134-137.

Primary

Secondary

RadialRake


SOLID CARBIDE END MILLS (STANDARD

HardnessHB

Material TypeGrade

SteelFree cutting steelsStructural steelPlain carbon steelAlloy steelAlloy steel, hardened & tempered steel

Stainless SteelFree machiningAustenit icFerritic & martensitic

Cast IronLamellar graphiteLamellar graphiteNodular graphite, Malleable cast ironNodular graphite, Malleable cast iron

TitaniumUnalloyedAlloyedAlloyed

NickelUnalloyedAlloyedAlloyed

CopperCopperBeta brass, bronzeAlpha brassHigh strength bronze

Aluminium AlloysWrought alloysCast alloys < 5% SiCast alloys > 5% Si < 10% SiCast alloys >10% Si

SyntheticsDuroplastics (short chipping)Thermoplastics (long chipping)Fibre reinforced synthetics

150100805030

504035

80608060

504025

302515

80808050

75754545

100100100

Recommended SurfaceSpeed in m/min for

Coated TungstenCarbide End Mills

< 120< 200< 250< 350> 350

< 250< 250< 300

< 150< 300< 200< 300

< 200< 270< 350

< 150< 270< 350

< 100< 200< 200< 470

< 100< 150< 120< 120

---

min max

< 400< 700< 850

< 1200> 1200

< 850< 850

< 1000

< 500< 1000< 700

< 1000

< 700< 900

< 1200

< 500< 900

< 1200

< 350< 700< 700

< 1500

< 350< 500< 400< 400

---

TensileStrength

N/mm2

2001501208050

807060

160120160120

806040

504020

120120120100

1351008080

300300300

TO CALCULATE:

RPM = (surface speed x 1000) / (π x d)FEED RATE in mm/min = rpm x feed per tooth x number of teeth

NOTE: For uncoated end mills reduce surface speed by 35% to 50%


Recommended feed in mm per tooth for Coated Tungsten Carbide End Millsbased on full diameter cutting width and half diameter cutting depth.

Use 50% of recommended feed rate for long series end mills.

0.0500.0500.0500.0500.050

0.0080.0080.006

0.0500.0500.0500.050

0.0800.0500.050

0.0300.0200.020

0.0500.0500.0500.025

0.0500.0500.0500.050

0.0500.0500.050

2

0.0500.0500.0500.0500.050

0.0100.0100.007

0.0500.0500.0500.050

0.0800.0500.050

0.0300.0200.020

0.0500.0500.0500.025

0.0500.0500.0500.050

0.0500.0500.050

4

0.0600.0600.0600.0500.050

0.0150.0150.010

0.0600.0500.0600.050

0.0800.0500.050

0.0450.0300.030

0.0700.0700.0700.035

0.1000.1000.1000.100

0.0700.0700.070

6

0.1000.1000.1000.0800.080

0.0700.0700.050

0.1000.0800.1000.080

0.1200.0800.080

0.0900.0600.060

0.1000.1000.1000.050

0.5000.5000.5000.500

0.1500.1500.150

25

0.0800.0800.0800.0500.050

0.0200.0200.015

0.0800.0600.0800.060

0.0800.0500.050

0.0450.0300.030

0.0700.0700.0700.035

0.2000.2000.2000.200

0.0800.0800.080

8

0.0800.0800.0800.0600.060

0.0300.0300.020

0.0800.0600.0800.060

0.0900.0600.060

0.0600.0400.040

0.0800.0800.0800.040

0.2000.2000.2000.200

0.0900.0900.090

10

0.1000.1000.1000.0800.080

0.0600.0600.045

0.1000.0801.1000.080

0.1200.0800.080

0.0900.0600.060

0.1000.1000.1000.050

0.5000.5000.5000.500

0.1500.1500.150

20

0.1000.1000.1000.0700.070

0.0500.0500.040

0.1000.0700.1000.070

0.1000.0700.070

0.0800.0500.050

0.0900.0900.0900.045

0.3000.3000.3000.300

0.1200.1200.120

16

0.1000.1000.1000.0600.060

0.0400.0400.030

0.1000.0600.1000.060

0.0900.0600.060

0.0800.0500.050

0.0800.0800.0800.040

0.2000.2000.2000.200

0.1000.1000.100

12

RANGE) TECHNICAL DATA

End Mill Diameter in mm


HardnessHB

Material Type

max

RecommendedSurface Speed

in m/mimn

min

TensileStrength

N/mm2

SOLID CARBIDE ROUGHING END

Free Cutting Carbon Steel0.3 to 0.4% Carbon Steel0.3 to 0.4% Carbon SteelAlloy SteelHardened Alloy Steel

Stainless Steel - Martensitic (400 Series)Stainless Steel - Austenitic (300 Series)

Grey Cast IronsNodular Cast IronsMalleable Cast Irons

Heat Resisting Alloys

Commercially Pure TitaniumCommercially Alloyed Titanium

15014012090

100

6080

120110100

20

5045

< 150< 170< 248< 330< 400

< 248< 300

110-300

< 350

< 275< 350

200190160150140

100100

160140130

40

8065

< 540< 620< 910< 1150

-

< 810< 1000

-

< 1000


Stainless Steel - Martensitic (400 Series)Stainless Steel - Austenitic (300 Series)


Commercially Pure Titanium

1501401209080

6080

120110100

50

< 150< 170< 248< 330< 400

< 248< 300

110-300

< 275

200190160150140

100100

160140130

80

SOLID CARBIDE ROUGHING END MILL

HardnessHB

Material Type

max


in m/mimnmin

TensileStrength

N/mm2

< 350< 400

Aluminium wrought alloysAluminium cast alloys > 5% Si < 10% Si

500500

< 100< 120

20001500

03C Solid Carbide 3 Flute Roughing End Mill REGULAR LENGTH, KNUCKLE FORM,

< 540< 620< 910< 1150

-

< 810< 1000

-

< 1200

< 1000< 1200

03D Solid Carbide 3 Flute Roughing End Mill REGULAR LENGTH, FLAT CREST,03F Solid Carbide 4 Flute Roughing End Mill REGULAR LENGTH, FLAT CREST, FINE

03E Solid Carbide 4 Flute Roughing End Mill REGULAR LENGTH, KNUCKLE FORM,


Recommended feed in mm per tooth for Coated Carbide End Millsbased on 1.0 x D cutting depth with 0.5 x D cutting width.

Reduce depth to 0.75 x D for slotting

6 8 10 12 2016


0.0440.0440.0360.0330.033

0.0290.036

0.0440.0360.029

0.019

0.0290.026

0.0600.0600.0500.0450.045

0.0400.050

0.0600.0500.040

0.026

0.0400.037

0.0720.0720.0610.0540.054

0.0480.061

0.0720.0610.048

0.032

0.0480.045

0.0830.0830.0700.0620.062

0.0560.070

0.0830.0700.056

0.037

0.0560.052

0.1140.1140.1010.0880.088

0.0810.101

0.1140.1010.081

0.054

0.0810.074

0.1010.1010.0870.0770.077

0.0700.087

0.1010.0870.070

0.046

0.0700.064

MILLS TECHNICAL DATA

0.0360.0360.0300.0270.027

0.0240.030

0.0360.0300.024

0.024

0.0490.0490.0410.0370.037

0.0330.041

0.0490.0410.033

0.033

0.0590.0590.0490.0440.044

0.0390.049

0.0590.0490.039

0.039

0.0980.0980.0870.0760.076

0.0700.087

0.0980.0870.070

0.070

0.0870.0870.0750.0660.066

0.0600.075

0.0870.0750.060

0.060

0.0720.0720.0610.0540.054

0.0490.061

0.0720.0610.049

0.049

Recommended feed in mm per tooth based on 1.0 x D cutting depth with0.5 x D cutting width. For slotting up to 1.0 x D, reduce depth by 30%

6 8 10 12 2016

FOR ALUMINIUM TECHNICAL DATA


0.0660.059

0.0880.079

0.2200.198

0.1760.158

0.1100.099

COARSE PITCH, UNCOATED (FOR ALUMINIUM)

0.1320.119

COARSE PITCH, COATEDPITCH, COATED

FINE PITCH, COATED


HardnessHB

Material Type

max


in m/mimn

min

TensileStrength

N/mm2

SOLID CARBIDE END MILLS FOR

< 350< 400


500500

< 100< 120

20001500

02A Solid Carbide 2 Flute End Mill REGULAR LENGTH, UNCOATED (FOR ALUMINIUM)

< 350< 400


500500

< 100< 120

20001500

02R Solid Carbide 3 Flute End Mill REGULAR LENGTH, UNCOATED (FOR ALUMINIUM)

< 350< 400


500500

< 100< 120

20001500

02S Solid Carbide 3 Flute Ball Nose End Mill REGULAR LENGTH, UNCOATED (FOR

< 350< 400


500500

< 100< 120

20001500

02U Solid Carbide 3 Flute Toroidal End Mill with Neck REGULAR LENGTH,


Stainless Steel - Martensitic (400 Series)

Stainless Steel - Austenitic (300 Series)

Duplex Steel


Heat Resisting Alloys

Commercially Pure TitaniumCommercially Alloyed Titanium

SOLID CARBIDE VARICUT END

Hard-nessHB

Material TypeSlot-ting

< 150< 170< 248< 330< 400

< 248250-450

< 230240-300

< 270

---

< 260270-350

< 275< 350

ae ap

1.5xD1.5xD1.5xD

0.75xD0.75xD

1.0xD0.75xD1.25xD1.25xD1.0xD

1.5xD1.25xD1.25xD

0.3xD0.3xD

1.25xD1.0xD

Parameters based on ideal conditions. Please adjust parameter accordingly to real applications.

Side Milling

ap

0.5xD0.5xD0.5xD0.5xD0.5xD


0.5xD0.5xD0.5xD

0.3xD0.3xD

0.5xD0.5xD



1.5xD1.5xD1.5xD

1.5xD1.5xD

1.5xD1.5xD

TensileStrength

N/mm2

< 540< 620< 910< 1150

-

< 810820-1350

< 700710-1000

< 900

---

< 1200< 1200

< 1000< 1200


Recommended feed in mm per tooth for Carbide End Millsbased on 1.0 x D cutting depth with 0.5 x D cutting width.

For slotting up to 1.0 x D, reduce depth by 30%

1 2 3 4 65


ALUMINIUM TECHNICAL DATA

0.0140.012

0.0180.016

0.0270.024

0.0540.049

0.0450.041

0.0360.032

8 1210

0.1080.097

0.0900.081

0.0720.065

16 20

--

0.1440.130

--

0.0180.016

0.0270.024

0.0540.049

0.0450.041

0.0360.032

0.1080.097

0.0900.081

0.0720.065

--

0.1440.130

--

--

0.0320.027

0.0600.054

0.0490.045

0.0410.036

0.1200.108

0.1000.090

0.0800.072

--

0.1600.144

--

--

0.0320.027

0.0600.054

0.0490.045

0.0410.036

0.1200.108

0.1000.090

0.0800.072

--

0.1600.144

ALUMINIUM)

UNCOATED (FOR ALUMINIUM)

Recommended feed in mm per tooth for Side Milling forCoated Carbide End Mills,. For Slotting reduce by 10% - 20%

0.0440.0440.0360.0330.033

0.0300.0250.0300.0360.025

0.0440.0360.030

0.0360.020

0.0300.025

6

0.0600.0600.0490.0450.045

0.0410.0340.0410.0490.034

0.0600.0490.041

0.0490.028

0.0410.034

8

0.0720.0720.0590.0540.054

0.0490.0410.0490.0590.041

0.0720.0590.049

0.0590.033

0.0490.041

10

0.0820.0820.0670.0620.062

0.0560.0470.0560.0670.047

0.0820.0670.056

0.0670.038

0.0560.047

12

0.1240.1240.1020.0930.093

0.0840.0710.0840.1020.071

0.1240.1020.084

0.1020.058

0.0840.071

25

0.1140.1140.0940.0860.086

0.0770.0650.0770.0940.065

0.1140.0940.077

0.0940.053

0.0770.065

20

0.1010.1010.0830.0760.076

0.0690.0580.0690.0830.058

0.1010.0830.069

0.0830.047

0.0690.058

16

MILL TECHNICAL DATA


1501401209080

6050609060

120110100

5025

6050


in m/minmin max

200190160150140

1007580

11570

150130130

9040

8060

0.0360.0360.0300.0270.027

0.0240.0210.0240.0300.021

0.0360.0300.024

0.0300.017

0.0240.021

5


SOLID CARBIDE HARD MATERIAL

RockwellC

HRCMaterial Type

Hardened Steels, IronsHardened Steels, Irons

12080


in m/min

< 4848-52

min max

140130

03G Solid Carbide 6 Flute Finishing End Mill REGULAR LENGTH, COATED

RockwellC

HRCMaterial Type


in m/minmin max


290200

< 4848-52

400350

03I Solid Carbide 2 Flute Ball Nose Finishing End Mill REGULAR LENGTH, COATED


290200

< 4848-52

400350

03J Solid Carbide 2 Flute Ball Nose Finishing End Mill LONG SERIES, COATED

RockwellC

HRCMaterial Type


in m/minmin max


10070

48-5252-62

120100

03H Solid Carbide Hi-Feed End Mill REGULAR LENGTH, COATED



Recommended feed in mm per tooth for Coated Carbide End Millsbased on 2.0 x D cutting depth with 0.15 x D cutting width

0.0360.027

6

0.0490.037

8

0.0590.044

10

0.1070.078

20

0.0840.063

16

0.0690.051

12

END MILLS TECHNICAL DATA


Recommended feed in mm per tooth for Coated Carbide End Millsbased on 0.03 x D cutting depth with 0.03 x D cutting width

4 6 8 10 201612


0.1000.080

0.1600.120

0.2200.160

0.2600.200

0.4300.320

0.3800.280

0.3000.230

0.1000.080

0.1600.120

0.2200.160

0.2600.200

0.4300.320

0.3800.280

0.3000.230

Recommended feed in mm per tooth for Coated Carbide End Mills based onAp1 max. For Circular Interpolation note min and max circle diameter range.

6 8 10 201612


0.2000.150

0.2500.200

0.3000.250

0.6000.500

0.5000.400

0.4000.300



CUTTER TECHNICAL DATA

MATERIALTYPE

GRADE

CARBONSTEEL

FREE CUTTING

0.3 to 0.4% Carbon

0.3 to 0.4% Carbon

0.4 to 0.7% Carbon

0.4 to 0.7% Carbon

HARDNESSHB

TENSILESTRENGTH

N / mm²

ALLOYSTEEL

150

170

248

206

286

510

580

830

675

970

248

330

381

833

1137

1265

STAINLESSSTEEL

Martensitic: Free Cutting Std. Grade

Austenitic: Free Cutting Std. Grade

As Supplied

248248

833833

TITANIUM

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Comm: Pure

Titanium Alloyed

Titanium Alloyed

Titanium Alloyed

NIMONICALLOYS

Wrought

Cast

300

350

1030

1200

170

200

275

340

350

380

510

660

940

1170

1200

1265


PERIPHERAL SPEED RANGE

PRIMARYCLEARANCE

† CUTTING ANGLES

8° - 20°

16-20

12-18

9-15

4-8

TYPE*A

TYPE*B

TYPE*C

TYPE*D

SECONDARYCLEARANCE

RADIALRAKE

30-40

24-32

18-25

24-32

16-25

28-40

24-32

18-25

24-32

16-20

24-32

20-26

14-20

20-26

12-20

30-40

24-32

18-25

24-32

16-25

Add 10°to

primary9° - 14°

16-20

12-18

8-14

12-16

10-15

8-12

16-20

10-16

8-12

8° - 20°Add 10°

toprimary

9° - 14°

10-205-10

10-205-10

12-165-10

12-165-10

8-154-8

8-154-8

10-205-10

10-205-10

8° - 20°Add 10°

toprimary

5-10 3-7 4-8 8° - 20° Add 10° toprimary

9° - 14°

9° - 14°

7-12 5-12 5-10 7-12 8° - 20°

Add 10°

to

primary

9° - 14°

CUTTER TECHNICAL DATA (cont.)

Explanatory Notes

*Cutter typesA - Shank CuttersB - Side and Face Cutters, Single and Double Angle Cutters, Slitting SawsC - Shell End Mills - Plain ToothD - Shell End Mills - RoughingNote: For Roughing End Mills see page 140-141.

† Cutting AnglesUse higher angles for smaller diameters, reducing proportionately for larger diameters.


MATERIALTYPE

GRADE

ALUMINIUMALLOYS

Wrought

Wrought

Cast

HARDNESSHB

TENSILESTRENGTH

N / mm²

COPPERALLOYS

55

110

100

PLASTICS

Brass : Free Cutting Low LeadedBronze: Silicon Manganese Aluminium PhosporCopper

As Supplied

As Supplied


TOOL STEEL

HSS Standard Grades

HSS Cobalt Grades

Hot Working Steel

Cold Working Steel

225

250

250

250

735

830

830

830

CASTIRONS

Grey, Malleable

Hardened

240

330

800

1137


PERIPHERAL SPEED RANGE

PRIMARYCLEARANCE

† CUTTING ANGLES

10° - 20°

40-7050-8040-7025-4515-2515-2540-70

TYPE*A

TYPE*B

TYPE*C

TYPE*D

SECONDARYCLEARANCE

RADIALRAKE

200-1500

100-250

40-100

120-180

100-180

50-70

50-180

50-100

30-80

Add 10°

to

primary

20° - 28°

8° - 20°Add 10°

toprimary

9° - 14°

50-200 50-200 10° - 20°Add 10°

toprimary

9° - 14°

35-4545-7035-4520-4015-2515-2535-45

30-6040-6530-6020-3512-2012-2030-60

8° - 20° 9° - 14°

10° - 20° 20° - 28°

Explanatory Notes

*Cutter typesA - Shank CuttersB - Side and Face Cutters, Single and Double Angle Cutters, Slitting SawsC - Shell End Mills - Plain ToothD - Shell End Mills - RoughingNote: For Roughing End Mills see page 140-141.

† Cutting AnglesUse higher angles for smaller diameters, reducing proportionately for larger diameters.


10-20

10-16

10-16

10-16

10-20

10-20

10-16

10-16

8-15

8-13

8-13

8-13

10-20

10-16

10-16

10-16

8° - 20°Add 10°

toprimary

9° - 14°

16-20

12-16

16-20

10-14

12-16

10-12

20-28

16-228° - 20°

Add 10° to

primary9° - 14°


FEEDS PER TOOTH Sz (mm):End Mills

345681012141618202225283032354050

EndMill

Table Shows Sz Values

CarbonSteels

AlloySteels

StainlessSteels

NimonicAlloys Titanium

0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130

0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130

0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130

0.0080.0120.0140.0180.0240.0290.0360.0400.0460.0520.0580.0640.0720.0810.0880.0920.1040.1040.104

0.0100.0150.0180.0220.0300.0360.0440.0510.0580.0650.0730.0800.0900.1020.1100.1160.1300.1300.130

Sz x 1.25 Sz x 0.78

ar = 0.1 x d ar = 0.25 x d

aa =

d

aa =

d

aaaa

For Peripheral Speed (m/min) see pages 134-137



ToolSteels

CastIrons

ManganeseSteels

AluminiumAlloys

CopperAlloys

0.0090.0130.0160.0200.0270.0320.0400.0460.0520.0580.0650.0720.0800.0910.1000.1040.1170.1170.117

0.0100.0160.0220.0280.0360.0400.0450.0560.0640.0700.0800.0880.0950.1100.1200.1270.1420.1420.142

0.0080.0120.0140.0180.0240.0290.0360.0400.0460.0520.0580.0640.0720.0810.0880.0920.1040.1040.104

0.0130.0190.0230.0280.0390.0460.0570.0660.0750.0850.0920.1040.1170.1320.1430.1500.1700.1700.170

0.0130.0190.0230.0280.0390.0460.0570.0660.0750.0850.0920.1040.1170.1320.1430.1500.1700.1700.170

Sz Sz

ar = d

aa =

0.5

x d

aa =

0.5

x d

aaaa

ar = d


End MillSize


Steels up to500N/mm²

Malleble CastIron up to 120

HB

Steels of500-800 N/mm²

Non - AlloyedTool Steels

Pure Titanium


Hot WorkingSteels

Cast Iron of120 - 180 HB

0.0080.0130.0170.0230.0260.0300.0320.0350.0350.0400.0420.0420.0450.0450.0470.060

28 - 40

681012141622252830323538404550

0.0080.0130.0200.0250.0300.0380.0400.0420.0450.0450.0500.0500.0570.0570.0590.074

24 - 32

0.0090.0150.0200.0250.0300.0380.0400.0420.0420.0450.0500.0500.0570.0570.0600.075

18 - 25

FEEDS PER TOOTH Sz (mm):Roughing End Mills

Peripheral Speed (m/min)

Sz Sz x 1.5 Sz x 1.8

d 0.3 d 0.5 d

d 1.5

d

1.5

d



Brass andBronze(Cast)

Brass andBronze(Rolled)

Plastics andsimilar

0.0080.0120.0170.0240.0260.0330.0380.0400.0400.0400.0440.0440.0480.0480.0480.060

35 - 45

0.0060.0090.0130.0160.0210.0240.0250.0280.0280.0300.0360.0360.0400.0400.0420.052

45 - 70

0.0060.0090.0120.0130.0150.0190.0220.0250.0250.0280.0350.0350.0350.0380.0400.047

200 - 250

Stainless Steels

Titanium Alloys(Annealed)

Cast Iron of morethan 180 HB

TitaniumAlloys

(Hardened)

0.0100.0150.0210.0330.0370.0440.0480.0500.0500.0560.0640.0640.0700.0700.0750.090

12 - 18

0.0130.0200.0300.0370.0470.0530.0600.0630.0650.0680.0800.0800.0860.0900.0940.119

7 - 12

Sz Sz x 1.5 Sz x 1.8

d 0.3 d 0.5 d

d 1.5

d

1.5

d


CutterDiameter


CutterWidth



HB



Pure Titanium


Hot WorkingSteels


0.0500.0520.0630.0640.0690.0700.0770.0780.0880.0900.0930.1010.1070.105

63

80

100

125

160

200

250

0.0510.0540.0630.0640.0690.0690.0780.0780.0900.0900.0930.1010.1070.105

0.0510.0540.0700.0700.0700.0700.0800.0800.1000.1000.1020.1020.1100.106

FEEDS PER TOOTH Sz (mm):Side and Face Cutters - Staggered Tooth

310412514716718818818

1018122014251628183218321832

over to

b0.

1 d






Plastics andsimilar

0.0500.0520.0630.0630.0700.0700.0800.0800.0900.0900.0930.1010.1080.104

0.0460.0480.0560.0560.0620.0700.0800.0800.0900.0900.0930.1010.1080.104

0.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.0200.020

Stainless Steels



TitaniumAlloys

(Hardened)

0.0500.0520.0630.0630.0700.0700.0780.0780.0900.0900.0930.1020.1080.104

0.0510.0530.0630.0630.0700.0700.0800.0800.0900.0900.0940.1020.1100.105

b

0.1

d


Type


CutterDiameter



HB



Pure Titanium


Hot WorkingSteels


0.0800.0800.1000.1000.1000.1000.105

40506380100125160

0.0800.0800.1000.1000.1000.1000.105

0.0800.0800.1000.1000.1000.1000.105

40506380100125160

0.0600.0700.0750.1000.1100.1150.120

0.0600.0700.0800.1000.1100.1150.120

0.0600.0700.0700.1000.1100.1150.125

0.75 d

0.1

d

Plain Tooth

PlainTooth

RoughingForm

FEEDS PER TOOTH Sz (mm):Shell End Mills






Plastics andsimilar

0.0800.0800.1000.1000.1000.1000.105

0.0800.0800.1000.1000.1000.1000.105

0.0220.0220.0220.0220.0220.0220.022

0.0600.0750.0800.1000.1100.1150.120

Stainless Steels



TitaniumAlloys

(Hardened)

0.0800.0800.1000.1000.1000.1000.105

0.0800.0800.1000.1000.1000.1000.105

0.0600.0750.0800.1000.1100.1150.120

0.0600.0750.0800.1000.1100.1150.120

0.0600.0750.0800.1000.1100.1150.120

0.0220.0280.0310.0390.0390.0420.044

0.75 d

0.15

d -

0.25

d

Roughing Form


v =

Sz =

rpm =

Sn =

S¹ =

V =

p =

v = speed (m/min)

D = cutter diameter (mm)

rpm = revolutions/min

Sn = feed/revolution (mm)

S¹ = feed/minute (mm)

Sz = feed/tooth (mm)

Z = number of teeth on cutter

V = chip volume (cm³/min)

a = depth of cut (mm)

b = length of cut (mm)

D. π. rpm1000

S¹rpm.Z

V. 1000π.D

S¹rpm

Sz. Z. rpm

a. b. S¹1000

3.1416

SPEED AND FEED FORMULAE


+12 0

+150

+18 0

+210

+250

+300

+350

+10 0

H7

+70-70

+60-60

+50-50

+42-42

+35-35

+24-24

3 to6mm

6 to 10mm

10 to18mm

18 to30mm

30 to50mm

50 to80mm

80 to120mm

-30-105

-40-130

-50-160

-65-195

-80-240

-100-290

-120-340

-20-38

-25-47

-32-59

-40-73

-50-89

-60-106

-72-126

0-75

0-90

0-110

0-130

0-160

0-190

0-220

0-120

0-150

0-180

0-210

0-250

0-300

0-350

+150 -150

+180 -180

+215 -215

+260 -260

+310 -310

+370 -370

+435 -435

+375 -375

+450 -450

+550 -550

+650 -650

+800 -800

+950 -950

+1100 -1100

3mm

-20-80

-14-28

d11

0-60

0-100

+300 -300

+125 -125

Tolerances in μm = 1 micron (1/1000mm)

DIAMETER OR WIDTH

0-6

0-14

0-8

0-9

0-11

0-13

0-16

0-19

0-22

0-18

0-22

0-27

0-33

0-39

0-46

0-54

+90-0

+110-0

+130-0

+160-0

+190-0

+220-0

+60-0

+75-0

+29-29

+20-20

e8

h11

h12

js16

h6

h8

k11

js14

Tol.

TOLERANCES

+120 -0

+150-0

+180 -0

+210-0

+250-0

+300-0

+350-0

+100 -0

K12

h7 0-10

0-12

0-15

0-18

0-21

0-25

0-30

0-35

k10 +400

+480

+580

+700

+840

+1000

+1200

+1400

js10

GENERAL INFORMATION

+900

+1100

+1300

+1600

+1900

+2200

+600

+750

H11


PERIPHERAL SPEED TO rpm CONVERSION CHART

METRESPER MIN

5 10 20 30 40

Dia.mm

123456789

1011121314151618202224262830354045506375

100

15917955303983182652271991771591451331221141061008980736761575345403532252116

31821590106079563653045539835331828926524522721219917715914513312211310691807064504232

6364318221201590127210609107967066365785304904544243983543182902662442282121821601401281008464

95464770318023851908159013651194105995486779573568163659753147743539936634231827324021019215012696

1272863604240318025442120182015921412127211561060980908848796708636580532488456424364320280256200168128



1591079505300397531802650227519901765159014451325122511351060995885795725665610570530455400350320250210160

50 70 80 90 10060

190929540636047703816318027302388211819081734159014701362127211941062954870798732684636546480420384300252192

222741113074205565445237103185278624712226202318551715158914841393123911131015931854798742637560490448350294224

2545612720848063605088424036403184282425442312212019601816169615921416127211601064976912848728640560512400336256

286381431095407155572447704095358231772862260123852205204319081791159314311305119710981026954819720630576450378288

31820159001060079506360530045503980353031802890265024502270212019901770159014501330122011401060910800700640500420320


PERIPHERAL SPEED TO rpm CONVERSION CHART (cont.)


INCH-MILLIMETER CONVERSION TABLE

3"m m

76.20076.59776.99477.39177.78878.18478.58178.97879.37579.77280.16980.56680.96281.35981.75682.15382.55082.94783.34483.74184.13884.53484.93185.32885.72586.12286.51986.91687.31287.70988.10688.503

2"m m

50.80051.19751.59451.99152.38852.78453.18153.57853.97554.37254.76956.16655.56255.95956.35656.75357.15057.54757.94458.34158.73859.13459.53159.92860.32560.72261.11961.51661.91262.30962.70663.103

1"m m

25.40025.79726.19426.59126.98827.38427.78128.17828.57528.97229.36929.76630.16230.59930.95631.35331.75032.14732.54432.94133.33833.73434.13134.52834.92535.32235.71936.11636.51236.90937.30637.703

0"m m

0.3970.7941.1911.5881.9842.3812.7783.1753.5723.9694.3664.7625.1595.5565.9536.3506.7477.1447.5417.9388.3348.7319.1289.5259.92210.31910.71611.11211.50911.90612.303

0 . . . . .1/64 . . . .1/32 . . . .3/64 . . . .1/16 . . . .5/64 . . . .3/32 . . . .7/64 . . . .1/8 . . . . .9/64 . . . .5/32 . . . .11/64 . . . .3/16 . . . .13/64 . . . .7/32 . . . .15/64 . . . .1/4 . . . . .17/64 . . . .9/32 . . . .19/64 . . . .5/16 . . . .21/64 . . . .11/32 . . . .23/64 . . . .3/8 . . . . .25/64 . . . .13/32 . . . .27/64 . . . .7/16 . . . .29/64 . . . .15/32 . . . .31/64 . . . .


INCH-MILLIMETER CONVERSION TABLE (cont)

3"m m

89.90089.29789.69490.09190.48890.88491.28191.67892.07592.47192.86893.26693.66294.05994.45694.85395.25095.64796.04496.44196.83897.23497.63198.02898.42598.28299.21999.616100.012100.409100.806101.203

2"m m

63.50063.89764.29464.69165.08865.48465.88166.27866.67567.07167.46867.86668.26268.85969.05669.45369.85070.24770.64471.04171.43871.83472.23172.62873.02573.42273.81974.21674.61275.00975.40675.803

1"m m

38.10038.49738.89439.29139.68840.08440.48140.87841.27541.67142.06842.46642.86243.85943.65644.05344.45044.84745.24445.64146.03846.43446.83147.22847.62548.02248.41948.81649.21249.60950.00650.403

0"m m

12.70013.09713.49413.89114.28814.68415.08115.74815.87516.27116.66817.06617.46217.85918.25618.65319.05019.44719.84420.24120.63821.03421.43121.82822.22522.62223.01923.41623.81224.20924.60625.003

1/2 . . . . .33/64 . . . .17/32 . . . .35/64 . . . .9/16 . . . .37/64 . . . .19/32 . . . .39/64 . . . .5/8 . . . . .41/64 . . . .21/32 . . . .43/64 . . . .11/16 . . . .45/64 . . . .23/32 . . . .47/64 . . . .3/4 . . . . .49/64 . . . .25/32 . . . .51/64 . . . .13/16 . . . .53/64 . . . .27/32 . . . .55/64 . . . .7/8 . . . . .57/64 . . . .29/32 . . . .59/64 . . . .15/16 . . . .61/64 . . . .31/32 . . . .63/64 . . . .


APPROXIMATE HARDNESS AND TENSILESTRENGTH CONVERSIONS

TENSILE STRENGTH

MPa orN/mm²

HRB HRC HV HB Tons/inch²

50556065707580859095100——————————————————————————

——————————202224262830323436384042444648505254565860646668707580

95100110120130140150165185205230240255265280295310325345360380405425450480505545580615655695790855940107514801865

90100105110120130140160175195220230240250265280290310325345365385405430455480———————————

212325272931343740455053565962656872757883889296102108112117122130135150163179197——

32035039042045048052057062069077082086091096010001050111011501200128013601420148015401670172018001890200021002320251027703030——

HRB = Hardness Rockwell BHRC = Hardness Rockwell CHV = Hardness Vickers. Also DPN, VPN, DPH, VPHHB = Hardness Brinell. Also BHN

Note: These values should be treated as approximate only and aresuitable for calculating speeds and feeds or for general informationpurposes. Do not use for treated high speed steel.


HARDNESS CONVERSION CHART FORHIGH SPEED STEEL

HV30 HRC HV30 HRC

736741746752757763769775780786792798804810817823829836842849

59-3/460

60-1/460-1/460-1/2

6161

61-1/461-1/261-3/4

6262-1/462-1/262-3/4

6363-1/463-1/263-3/4

6464-1/4

856862869876883890897905912919927934942950958966974982990999

64-1/263-3/4

6565-1/465-1/2

6666

66-1/26767

67-1/467-1/2

6868

68-1/268-1/2

6969-1/269-1/2

70

Typical hardness

HSS (M2) 823-876 HV30 - 63-65 HRCHSS-Co5 (M35) 849-920 HV30 - 64-66 HRCHSS-Co8 (M42) 897-966 HV30 - 66 - 68-1/2 HRC

Depending on the nature of the tool these hardnesses may bevaried, particularly in the case of special tools where differenthardnesses may be specified.

Note:Undue reliance should not be placed on a general conversionchart unless it has been tested for a particular material. Theabove chart applies specifically to High Speed Steel.


USEFUL FORMULAE

rpm = Surface Speed (metres/min) ÷Dia (mm) x π

1000

Surface Speed (metres/min) = x rpmDia (mm) x π

1000

Feed Rate (mm/rev) =Feed rate (mm/min

rpm

Penetration rate (mm/min) = rpm x feed rate (mm/rev)


Trigonometry

Formulae for the solution of Formulae for the solution ofRIGHT ANGLED OBLIQUE ANGLEDTRIANGLES TRIANGLES

A

B C

cb

a

θθθθθ

A

B C

c

a

b

Tan θ θ θ θ θ =

Sin θ θ θ θ θ =

Cos θ θ θ θ θ =

oppositeadjacent

oppositehypotenuse

adjacenthypotenuse

=

=

=

ca

cb

ab

The Sine rule: a b cSin A Sin B Sin CThe Cosine rule:a² = b² + c² - 2bc Cos Ab² = a² + c² - 2ac Cos Bc² = a² + b² - 2ab Cos C

= =

USEFUL VALUES IN TRIGNOMETRICAL RATIOSFor right angled triangles

60°

30°

12

45°

45°1

1√ 3

√ 2

ANGLES 30° - 45° - 60°

θθθθθ Tan θθθθθ Sin θθθθθ Cos θθθθθ

30°

45°

60°

13

12√ = 0.577350 = 0.500000

32

√= 0.866025

1 12√ = 0.707107

12√ = 0.707107

3 = 1.732051√ 32

√= 0.866025

12 = 0.500000


Useful formulae for FindingDimensions of Circles, Squares, etc.

D is diameter of stock necessary to turn shape desired.E is distance “across flats,” or diameter of inscribed circle.C is depth of cut into stock turned to correct diameter.

C

E

D

CE

D

CE

D

CE

D

C

E

D

TRIANGLE

E = side x 0.57735D = side x 1.1547 = 2ESide = D x 0.866C = E x 0.5 = D x 0.25

SQUARE

E = side = D x 0.7071D = side x 1.4142 = diagonalSide = D x 0.7071C = D x 0.14645

PENTAGON

E = side x 1.3764 = D x 0.809D = side x 0.7013 = E x 1.2361Side = D x 0.5878C = D x 0.0955

HEXAGON

E = side x 1.7321 = D x 0.866D = side x 2 = E x 1.1547Side = D x 0.5C = D x 0.067

OCTAGON

E = side x 2.4142 = D x 0.9239D = side x 2.6131 = E x 1.0824Side = D x 0.3827C = D x 0.038


SQUARE

A = areaA = S² = 1/2 d²S = 0.7071d = √Ad = 1.414S = 1.414 √A

RECTANGLE

A = areaA = ab = a √d² - a² = b √d² - b²d = √a² + b²a = √d² - b² = A ÷ bb = √d² - a² = A ÷ a

RIGHT ANGLED TRIANGLE

A = areaA = bc 2a = √b² + c²b = √a² - c²c = √a² - b²

ACUTE ANGLED TRIANGLE

A = area

A =

if S = ( a + b + c ) then,

A = √S(S -a) (S - b) ( S - c)

Areas ofPlane Figures

a² - ( )12

s

s

d

d

b

a

c

b

a

c

b

a

hbh2 =

b2 √

a² + b² - c²2b

²


OBTUSE ANGLED TRIANGLE

A = area

A =

if S = ( a + b + c ) then,

A = √S(S -a) (S - b) ( S - c)

CIRCLE

A = area C = circumferenceA = π r² = 3.1416 r²

A = = 0.7854 d²

C = 2 πr = 6.2832r = 3.1416d

r = C ÷ 6.2832 = √A ÷ 3.1416 = 0.564 √A

d = C ÷ 3.1416 = √A ÷ 0.7854 = 1.128 √A

REGULAR HEXAGON

A = areaR = radius of circumscribed circler = radius of inscribed circleA = 2.598S² = 2.598R² = 3.464r²R = S = 1.155rr = 0.866S = 0.866R

= a² - ( )√

c² - a² - b²2b

²

12

b2

c

b

a

rd

h

r

60°R

s

π d²4

The construction of a regular hexagon forms six equilateral triangles,thusthe area of the hexagon can also be found by calculating the area of theequilateral triangle and multiplying the result by six.

bh2


Cone of Included Angle Angle with Centre Line

1 in 22-1/21 in 33-1/21 in 44-1/21 in 55-1/21 in 66-1/21 in 77-1/21 in 88-1/21 in 99-1/2

1 in 101 in 111 in 121 in 131 in 141 in 151 in 161 in 171 in 181 in 191 in 201 in 251 in 301 in 351 in 401 in 451 in 481 in 501 in 551 in 60

28°22°18°16°14°12°11°10°9°8°8°7°7°6°6°6°5°5°4°4°4°3°3°3°3°3°2°2°1°1°1°1°1°1°1°

4´37´55´15´15´40´25´23´31´47´10´37´9´43´21´1´43´12´46´24´5´49´34´22´10´0´51´17´54´38´25´16´11´8´2´57´

20″12″28″38″0″

50″16″20″36″52″16″43″10″58″34″32″31″18″19″16″26″6″

48″9″

58″54″52″31″36″14″56″24″37″46″29″17″

14°11°9°8°7°6°5°5°4°4°4°3°3°3°3°3°2°2°2°2°2°1°1°1°1°1°1°1°

2´18´27´7´7´

20´42´11´45´23´5´

48´34´21´10´0´

51´36´23´12´2´

54´47´41´35´30´25´8´

57´49´42´38´35´34´31´28´

10″36″44″49″30″25″38″40″48″56″8″52″35″59″47″46″46″9″9″8″43″33″24″4″29″27″56″46″18″7″58″12″48″23″14″39″

USEFUL TAPERS


MO

RS

E T

AP

ER

S A

ND

BR

OW

N &

SH

AR

PE

TA

PE

RS

Tape

rN

umbe

rTa

per

Per

mm

on

dia.

Tape

r P

erfo

ot o

n di

a.In

clud

ed A

ngle

Ang

le t

o C

entr

e Li

neD

eg.

Min

s.S

ecs

.D

eg.

Min

s.S

ecs

.

Mo

rse

1 2 3 4 5 6

Bro

wn

&S

ha

rpe

4 5 7 9 10 11 12

0.04

9881

0.04

9951

0.05

0196

0.05

1938

0.05

2626

0.05

2137

0.04

1867

0.04

1800

0.04

1789

0.04

1737

0.05

1343

0.04

1750

0.04

1644

0.59

858

0.59

941

0.60

235

0.62

326

0.63

151

0.62

565

0.50

240

0.50

160

0.50

147

0.50

085

0.51

612

0.50

100

0.49

973

2 2 2 2 3 2 2 2 2 2 2 2 2

51 51 52 58 0 59 23 23 23 23 27 23 23

27 41 31 31 52 12 54 41 39 28 50 30 08

1 1 1 1 1 1 1 1 1 1 1 1 1

25 25 26 29 30 29 11 11 11 11 13 11 11

43 50 16 15 26 36 57 50 49 44 55 45 34


CONVERSION FACTORS

British - MetricTo convert Multiply byInches to millimetres 25.40Feet to metres 0.3048Yards to metres 0.9144Miles to kilometres 1.60934Square inches to square centimetres 6.4516Square feet to square metres 0.092903Square yards to square metres 0.836127Square miles to square kilometres 2.58999Cubic inches to cubic centimetres 16.3871Cubic feet to cubic metres 0.028317Cubic yards to cubic metres 0.764555Pints to litres 0.568261Gallons to litres 4.54609Ounces to grams 28.3495Pounds to kilograms 0.453592Tons to tonnes (1.000kg) 1.01605Lb/sq.in. to kg/sq.m 703.070Fahrenheit = 9/5°C+32

Metric - BritishTo convert Multiply byMillimetres to inches 0.0393701Metres to feet 3.28084Metres to yards 1.09361Kilometres to miles 0.621371Square centimetres to square inches 0.1550Square metres to square feet 10.76391Square metres to square yards 1.19599Square kilometres to square miles 0.3861Cubic centimetres to cubic inches 0.061024Cubic metres to cubic feet 35.3147Litres to pints 1.76Litres to gallons 0.22Grams to ounces 0.035274Kilograms to pounds 2.20462Tonnes to tons 0.984207Kg/sq.mm to lb/sq.in. 0.001422Centigrade (Celcius) = 5/9° (F-32)


.1mm

.2mm

.3mm8079

1/64.4mm

7877

.5mm767574

.6mm737271

.7mm706968

1/32.8mm

676665

.9mm64636261

1mm6059585756

3/64555453

1/165251504948

5/6447

2mm46

Decimal Equivalentsmm-Inch-Wire

.0039

.0079

.0118

.0135

.0145

.0156

.0157

.0160

.0180

.0197

.0200

.0210

.0225

.0236

.0240

.0250

.0260

.0276

.0280

.0292

.0310

.0312

.0315

.0320

.0330

.0350

.0354

.0360

.0370

.0380

.0390

.0394

.0400

.0410

.0420

.0430

.0465

.0469

.0520

.0550

.0595

.0625

.0635

.0670

.0700

.0730

.0760

.0781

.0785

.0787

.0810

DecimalInch

mm-Inch-Wire

DecimalInch

mm-Inch-Wire

DecimalInch

mm-Inch-Wire

DecimalInch

45444342

3/32414039383736

7/6435343332

3mm311/8302928

9/642726252423

5/3222

4mm21201918

11/641716151413

3/161211109

5mm87

13/646

.0820

.0860

.0890

.0935

.0938

.0960

.0980

.0995

.1015

.1040

.1060

.1094

.1100.1110.1130.1160.1181.1200.1250.1285.1360.1405.1406.1440.1470.1495.1520.1540.1562.1570.1575.1590.1610.1660.1695.1719.1730.1770.1800.1820.1850.1875.1890.1910.1935.1960.1969.1990.2010.2031.2040

543

7/3221A

15/646mm

BCD

1/4 & EFG

17/64HI

7mmJK

9/32LM

19/64N

5/168mm

OP

21/64QR

11/32S

9mmT

23/64U3/8VW

25/6410mm

XY

13/32Z

27/6411mm7/16

.2055

.2090

.2130

.2188

.2210

.2280

.2340

.2344

.2362

.2380

.2420

.2460

.2500

.2570

.2610

.2656

.2660

.2720

.2756

.2770

.2810

.2812

.2900

.2950

.2969

.3020

.3125

.3150

.3160

.3230

.3281

.3320

.3390

.3438

.3480

.3543

.3580

.3594

.3680

.3750

.3770

.3860

.3906

.3937

.3970

.4040

.4062

.4130

.4219

.4331

.4375

29/6415/3212mm31/641/2

13mm33/6417/3235/6414mm9/1637/6415mm19/3239/645/8

16mm41/6421/3217mm43/6411/1645/6418mm23/3247/6419mm

3/449/6425/3220mm51/6413/1621mm53/6427/3255/6422mm

7/857/6423mm29/3259/6415/1624mm61/6431/3225mm63/64

1”

.4531

.4688

.4724

.4844

.5000

.5118

.5156

.5313

.5469

.5512

.5625

.5781

.5906

.5938

.6094

.6250

.6299

.6406

.6562

.6693

.6719

.6875

.7031

.7087

.7188

.7344

.7480

.7500

.7656

.7812

.7874

.7969

.8125

.8268

.8281

.8438

.8594

.8661

.8750

.8906

.9055

.9062

.9219

.9375

.9449

.9531

.9688

.9843

.98441.0000

NUMBER AND LETTER DRILL SIZES

Head Office and Surface Coating Division

Somta House, 290-294 Moses Mabhida (Edendale) Road, Pietermaritzburg, 3201Private Bag X401, Pietermaritzburg, 3200South Africa

Tel: Factory: +27 33 355 6600Fax: Factory: +27 33 394 0564Tel: Sales: +27 11 390 8700 (Local)Fax: Sales: +27 11 397 6720/1 (Local)Email: [email protected] (Local)Tel: Sales: +27 33 355 6600 (Exports)Fax: Sales: +27 33 394 7509 (Exports)Email: [email protected] (Exports)

Gauteng Sales Office

43 Bisset Road, Hughes Ext. 7, Boksburg, 1459P.O.Box 14212, Witfield, 1467South Africa

Tel: +27 11 390 8700Fax: +27 11 397 6720/1Sharecall: 086 010 4367Email: [email protected]

Technical Information:

Email: [email protected] Free Number: 0800-331-399Technical Representatives Cell Numbers: 082 801 8930, 082 800 5259, 082 906 3486082 806 8202, 082 803 0505

Manufacturers & Suppliers

of Drills, Reamers, End Mills,

Bore Cutters, Taps & Dies,

Toolbits, Solid Carbide

Tooling, Carbide Insert

Tooling, Custom Tools

and Surface Coatings

ISO

9 001

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