EME1226

WORKSHOP TECHNOLOGY

EXPERIMENT 1: Machining and

Handtools

(Making a pin hammer)

PREPARED BY:

KIAT ANN SHUN

(ID#1122702045)

Abstract

In this experiment, I had made a pin hammer with my group member in

mechanical workshop with various machining process by using hand tools and

machines. At first, we cut the raw material into an approximately 225mm rod by using

steel cutter. Next we measured and cut the rod into 2 parts by using vernier caliper,

hacksaw and bench vices. For the head part, we cut the smaller rod into rectangular with

two 15mmX15mm square heads and one of heads was cut with 30 degree by using

milling machine. After that, we drilled a hole on the middle part of the hammer head by

using punch, hammer and drilling machines. Meantime, by using turning machine, the

length and diameter of the long rod were cut into the exact dimensions for the hammer

handle. Moving on, by using various types of dies, we make tracks on the smallest

diameter part of the handle and the middle hole of the hammer head. After the tracks

were done and the two parts were assembled which mean our hammer is finished. Lastly

we polish the hammer with sand paper for finishing process.

Table of contents

No ContentsPage

No.

1 Introduction 2

2 Theoretical Background 3-5

3 Equipments 6

4 Procedure 6-9

5 Data and Results 10

6 Discussions 11

7 Conclusions 12

8 Recommendation 12-13

9 List of References. 14

10 Appendices 15

Introduction

In this experiment, we are guided to learn the right techniques and familiar to

various machining processes, hand tools and machines in order to finish the hammer in

mechanical workshop. Before any step is taken by us, we were briefed by lecturer and

technician about the techniques and precaution steps to ensure our safety. After the brief

and precaution steps, we can start to do the hammer which means we start to handle the

tools and machines by ourselves. This helps us to understand and familiar to uses and

right ways to handle the tools and machines. After the experiment, we learned how to

apply the workshop safety, bench work, marking and the techniques to handle the tools

and machines.

Theoretical Background

To make the hammer, we had to learn various machining process included turning

process, milling process drilling and treading.

Turning process

Turning is a machining and material removal process. Turning is used to create the

rotational parts by cutting away unwanted materials. The turning process requires

turning machine or lathe, work piece, fixture, and cutting tools. The work piece is the

pre-shaped material that is secured to the fixture, which is attached to the turning

machine, and allowed to rate at high speeds. The cutter is typically a single-point cutting

tool that is also secured in the machine, although some operations make use of multi-

point tools. The cutting tool moves into the rotating work piece and cuts away material

in the form of small chips to create the desired shape. 

Facing process

Facing process is the removing process by which the single-point turning tool moves

radically, along the end of the work piece, removing a thin layer of material to provide a

smooth flat surface and decrease the length. To safely perform a facing operation the end

of the work piece must be positioned close to the jaws of the chuck.

Milling process

Milling is the machining process of using rotary cutters to remove material from a work

piece feeding in a direction at an angle with the axis of the tool. Milling process requires

milling machine, work piece, fixture, and cutter. The work piece is a piece of pre-shaped

material that is secured to the fixture, which itself is attached to a platform inside the

milling machine The cutter is a cutting tool with sharp teeth that is also secured in the

milling machine and rotates at high speeds. Milling process is used to cut away

unwanted part of the work piece to a desired piece.

Drilling process

Drilling is a process in which a drill

enters the work piece axially and produces a circular hole with a diameter equal to that

of the tool. The machine used for drilling is called drilling machine. The drilling

operation can also be accomplished in lathe, in which the drill is held in tailstock and the

work is held by the chuck. The most common drill used is the twist drill.

Treading

Threading is the process of creating a screw thread. A common method of threading is

cutting with taps and dies. Rotating a tap enters the work piece axially and cuts internal

threads into an existing hole. The existing hole is typically drilled by the required tap

drill size that will accommodate the desired tap.

Equipments and materials

Raw material (mild steel), files, hacksaw,

cutter, set of taps, tap wrench, sand paper,

drilling machine, turning machine,

milling machine and grinding machines.

Procedure

First of all, the raw material (mild steel) is measured and marked approximately

225mm, and cut by using vernier calliper and steel cuter.

Next the steel rod is measured about 160mm from one side end and cut by using

vernier calliper ,bench vice and hacksaw.

After that the smaller part was marked by 60mm from one side and drew

15mmX15mm squared on one head with vernier calliper. By using milling machine, the

smaller part was cut into a rectangular with 2 15mmX15mm squared heads. Moving on,

one side of the head was measured and marked 6mm from bottom. The fixture of the

milling machine was adjusted to 30 degree to cut a 30 degree surface of the head.

Next, the hammer head was marked a canter point from the top surface by using

vernier calliper. The hammer head was drilled a hole by using drilling machine.

Lubricant was used to prevent the drill and rob from overheated.

For the handle part, the longer rod was marked 160mm, 145mm and 80mm by

using vernier calliper. The rod was fixed into the fixture in turning machine and cut to

exact 160mm by using facing process. After that, the diameter of rod was reduce to

18mm for 80mm, 16mm for 65mm and 9.5mm for 15mm.

Moving on, handle was clamped

into bench vice and thread was made on

the 9.5mm diameter part of the handle by

using tap wrench.

Next, hammer head was clamped into bench vice and thread was made in

the drilled hole in the hammer head by using tap wrench..

After that, the two parts of the hammer were assembled. The surface of the

hammers was polish by sand paper.

Data and result

Parts Dimension(mm)

Hammer handle length (whole) 160.0

Hammer handle lengths 7.98,145.4

Diameter 18.2,15.5,9.5

Hammer head length 6.00

Hammer Squared heads 15.4X15.0

Discussion

In the turning process, our cutting fluid of turning machines was out of service.

Therefore our rod was always in high temperature and this make the cutter become dull.

So, our handle part was rough surface finish and not in exact dimension. The excessive

tool wear was cause by cutting parameters too high and lack of cutting fluid. The rough

surface finish is caused by feed too high and cutter lacks stiffness. The dimensional

variability was caused by the cutter tool lacks stiffness and excessive temperature rise.

In the milling process, the defects in milling operation may cause the work piece

inaccuracies in dimensions and surface roughness. There are some possible causes for

these errors. First, incorrect cutting parameters, for instance the cutting parameters such

as the feed rate, spindle speed, or axial depth of cut are too high; the surface of the work

piece will be rough. Next, as a cutter is used, the teeth will wear down and become dull.

A dull cutter is less capable of making precision cuts. Moving on, if the work piece was

not securely clamped in the fixture, the friction of milling may cause it to shift and alter

the desired cuts.

In the drilling process, there are some common errors encountered. First drill

breakage which caused by dull drill, feed to high and seizing in hole which chips

cogging. Next, excessive drills wear due to high cutting speed, ineffective of cutting

fluid, the drill become dull when the heat is too high. Tapered or oversized hole was

caused by dull drill and drill misaligned.

The effect of friction, temperature and vibration of the machines and tools

dominate machining accuracy in fine cutting. These errors were not predictable at the

machine design stage because the error mainly was caused by misalignment during

machine assembly and thermal expansion during operation.

Conclusion

In nutshell, we had learned the techniques and familiar to various types of hand

tools and machines. We also learned the various types of machining process such as

milling, turning, facing, drilling and threading.

Recommendations

To improve the turning process, we should minimize tool overhang, clamp the

work piece rigidity, use cutter with high stiffness, use the right cut parameter for turning

speed ,cut angle and feed rate, and use the cutting fluid.

For the milling machines, the work piece must be secured in the vice and use the

right cut parameter for turning speed and feed rate.

For the drilling process, the cutting fluid must be used and drill the work piece

steadily.

For safety purpose, there is some precaution steps should be taken before or

during or after using the any machine. Users should read the owner’s manual carefully.

Safety glasses and apron should be wears appropriate by users. The work piece should

be secured in the vice or fixture. Ensure that the start/stop button within reach range.

Ensure that the work piece and cutter are mounted securely before taking start the

operator. Use a vacuum, brush or rake to remove the cuttings only after the machines

have stopped moving or turning. Keep working surface clear of scraps, tools and

materials. Keep cutters sharpened correctly and in good condition. Change cutting

compounds periodically. Keep floor around the machine free of oil and grease.

For precaution steps, do not wear any loose clothing or ties. Roll sleeves above

the elbow to prevent them from being caught in revolving parts. Confine long hair, Do

not wear gloves, rings, watches, or bracelets while working with a drill press, do not set

speeds, adjust, or measure work until machine is completely stopped.

For safety steps for milling machines, mount work in a vice that is bolted or held

magnetically to the table, use proper hand tools to make adjustments, move table as far

as possible from cutter while setting up work to avoid injuring your hands, mill the

largest surface first, keep hands, brushes and rags away from the revolving milling

cutter, ensure the cutter is rotating in the right direction.

For safety principle for turning machines, follow job specifications for the speed,

feed and depth of cut for materials being turned, make sure all work runs true and

cantered, secure and clamp the piece being worked, remove chuck wrench immediately

after adjusting chuck, keep all lathe cutting tools sharp, ensure that the chip and coolant

shields are in place, stop machine before taking measurements of any kind, and use the

cutting fluid.

For safety precaution steps for drilling machine, remove burrs and chips from a

drilled hole, when making deep holes, clean out the hole frequently, use a clamp or drill

vise to prevent work from spinning, make sure the drill bit or cutting tool is locked

securely in the chuck. Remove the chuck key before starting the drill press, lubricate

drill bit when drilling metal, reduce the drilling pressure when the drill begins to break

through the work piece. This action prevents drill from pulling into the work and

breaking, keeps drill bits clean and sharp. Dull drills are a common cause of breakage.

When making the threads using the tap or the die, start the thread with a

perpendicular positioning of the tap or the die, turn the tap or die in quarter turns and

"back off" quarter turns to remove melt chips so that they don't clog the tool, and always

use cutting oil.

Reference

http://www.custompartnet.com/wu/turning

http://www.ccohs.ca/oshanswers/safety_haz/metalworking/

http://en.wikipedia.org/wiki/Threading_(manufacturing)#Thread_forming_and_rolling

Appendices