scan draft skill

8/12/2019 Scan Draft Skill

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Fig.1-1-2 Draftingtable anddesk

naddition to such special' 'work stations,

a variety of individual desks, chairs, tracing

tables, filing cabinets, and special storage

devices for drawings are available.

The simplest manually adjustable tables ty-

pically consist of a hinged surface riding on

a vertical rod secured by a setscrew. The set-

screw is loosened, the top is set at the desired

angle, and the setscrew is retightened.

Drafting Machines. n the well-equipped

drafting department, where the architect

designer is expected to do accurate drafting,

the T square has been replaced largely by the

drafting machine. This device, which com-

bines the functions of T square, set squares,

scale, and protractor, is estimated to save up

to 50 % of the user's time. All positioning is

done with one hand, while the other is free to

draw.

Keuffe l and Esser Co

Fig. 1-1-3 Arm type drafting machine

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Drafting machines may be attached to any

drafting board or table. Two types are cur-

rently available.

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the track type, a vertical

beam carrying the drafting instruments rides

along a horizontal beam fastened to the top of

the table.

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the arm, or elbow type (Fig.

1-1-3), two arms pivot from the top of the

machine and relative to each other.

Track-type drafting machines are especially

suitable for long-line work and large draw-

ings.

Straightedges. The straightedge is used in

drawing horizontal lines and for supporting set

squares when vertical and sloping lines are be-

ing drawn. See Fig. 1-1-4. It is fastened on

each end to cords, which pass over pulleys.

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ddressograoh Multigraph Corp

Fig. 1-1-4 Drafting table with straightedge

Drafting Skills

This arrangement permits movement of the

straightedge up and down the board while

maintaining the straightedge in a horizontal

position.

T Squares. The T square (Fig. 1-1-5.1per-

forms the same function as the parallel

straightedge. While you are using the T

square, keep the head of the instrument firmly

against the side of the board to ensure that the

lines you draw will be parallel. The head will

be on the left edge of the board if you are

right-handed and on the right if you are left-

handed.

T SQU R

Fig.1-1-5 T Square

Set Squares. Set squares are used together

with the parallel straightedge or T square

when you are drawing vertical and sloping

lines (Fig. 1-1-6). The set squares most com-

monly used are the 60-30 and the 45 set

squares. Singly or in combination, these set

squares can be used to form angles in all the

multiples of 15. For other angles, the protrac-

tor is used. All angles can be drawn with the

adjustable set square (Fig. 1-1-7); this instru-

ment replaces the two common set squares

and the protractor.

Scales. Shown in Fig. 1-1-8 are the common

shapes of scales used by drafters to make

measurements on their drawings. Scales are

used only for measuring and are not to be used


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(A) THE 45 SET SQUARE

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(B) THE 60 SET SQUARE

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Fig. 1-1-6

The set squares

(C) THE SET SQUARES IN COMBINATION

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Drafting Office and Equipment

Charles runing Co Canada Ltd

Fig. 1-1-7 Adjustable set square

for drawing lines. It is important that drafters

draw accurately to scale. The scale to which

the drawing is made must be indicated in the

title block or strip.

When objects are drawn at their actual size,

the drawing is called full scale or scale 1:1.

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RELIEVED F CET

TRIANGULAR SCALES

DOU LE EVEL OPPOSITE EVEL FL T EVEL

FL T

SCALES

Fig. 1-1-8 End view shapes of scales

Many objects, however, such as buildings, are

too large to be drawn full scale, so they

must be drawn to a reduced scale. An example

would be the drawing of a house to a scale of

1:50. See Fig. 1-1-9.

Frequently, small objects are drawn larger

than their actual size so that their shape can

be seen clearly. Such a drawing has been

drawn to an enlarged scale. The minute hand

of a wrist watch, for example, could be drawn

to scale 10:1.

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left on the drawing. See Fig. 1-1-16. Through

the use of this device, erasures can be per-

formed quickly and accurately.

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Keuf fel and Esser Co

Fig. 1-1-16 Erasing shield

Brushes. A light brush (Fig. 1-1-17) is used to

keep the drawing area clean. By using a brush

to remove eraser particles and any accumu-

lated dirt, the drafter avoids smudging the

drawing.

Charles Bruning Co Canada Ltd

Fig.I-I -17 Draf ters brush

Lettering Aids. Lettering sets or guides (Fig.

1-1-18) are also used when it is desirable to

have more uniform and accurate letters and

numerals than can be obtained by the free- -

hand method. Lettering sets contain a number

of guide templates that give a variety of letter

shapes and sizes, as well as different slope

angles.

Instant Lettering is a new method of dry

transfer lettering which offers a wide variety

of lettering at good quality and speed. It

adheres firmly to paper, wood, glass, and

metal and is available in different colours. In

case of errors. letters can be removed with

cellophane tape or a.pencil eraser.

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Addressograph Multigraph Corp

MECHANICAL LETTERING

LETRASETx272

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ABC 0 E F GH I J K

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APPLIQUES

Fig. 1-1-18 Lettering aids

Lettering typewriters have been used in

drafting offices for some time for the lettering

of bills of material and typing on appliques.

But now small, movable typewriters can letter

anywhere on the drawing without the need for

removing the drawing from the board.

Templates. To save time, many drafters

now use templates for drawing small circles

and arcs. Templates are also available for

drawing standard square, hexagonal, trian-

gular, and elliptical shapes and standard elec-

trical and architectural symbols. See Fig.

1-1-19.

Drafting Skills

F ig. 1-1-19 Templates

Rapid Design

Irregular Curves. For drawing curved lines

in which, unlike circular arcs, the radius of

curvature is not constant, an instrument

known as an irregular or French curve (Fig.

1-1-20) is used. The patterns for these curves

are based on various combinations of ellipses,

spirals, and other mathematical curves. The

curves are available in a variety of shapes and

sizes. Generally, the drafter plots a series of

points of intersection along the desired path

and then uses the French curve to join these

points so that a smooth-flowing curve results.

Teledyne Post

Fig. 1-1-20 Irregular curves

Inking Equipment. Although most produc-

tion drawings are drawn with pencil, in the

last few years ink drawings have been on the


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increase. The use of this type of drawing for

technical illustrations and the demand for

good, clear drawings for microfilming have

brought about the introduction of new and im-

proved inking methods and techniques. Typ-

ical ink equipment is shown in Fig. 1-1-21.

Two types of pens are used to produce ink

Jines. The ruling pen with an adjustable blade

for drawing different-width lines has been

available for many years. It is filled by a

dropper cap, squeeze bottle, or cartridge tube.

Inking compasses are available with perma-

nent or detachable blades, which interchange

with the lead attachment part of the compass.

Specially designed pens for drawing curved,

multiple broken or hidden lines are also

available.

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