Drawing Instruments and Accessories: Information with example

Drawing Instruments:

The Instruments and other aids used in draughting work are listed below: 
  1. Drawing board
  2. Mini draughter
  3. Instrument box 
  4. Set squares
  5. Protractor
  6. Set of scales 
  7. French curves
  8. Drawing sheets
  9. Pencils 
  10. Templates

Drawing Board:

Until recently drawing boards used are made of well seasoned softwood of about 25 mm thick with a working edge for T-square. Nowadays, mini draughter are used instead of T-Square that can be fixed on any board. The size of the board depends on the size of the drawing sheet size.
Drawing Board with mini-draughter
figure: Drawing Board with mini-draughter


The mini-drawer consists of two hand-drawn angles whose scales are marked and tightly connected to each other. It combines the functions of T-square, set-square, scale and protractor. It is used to draw horizontal, vertical and inclined lines, parallel and vertical lines and to measure lines and angles.
Mini draughter
source: amazon.com

Instrument Box:

Instrument box contains:

  1. Compasses
  2. Dividers
  3. Inking pens.
figure: Sharpening and position of compass lead
figure: Sharpening and position of compass lead
The position of the pencil lead is important with respect to the tip of the compass. It should be at least 1 mm as shown in the figure, as the tip goes into the board to catch 1 mm.
figure: Position of the lead leg to draw larger circles

Set of Scales: 

Scales are used to draw objects according to the desired size of the scale. These are made of wood, steel or plastic. BIS recommends eight set-scale in plastic / cardboard with designations like MI, M2 etc. as shown In the table (set of scales)
Scale on one edge Scale on other edge
M1 1:1 1:2
M2 1:2.5 1:5
M3 1:10 1:20
M4 1:50 1:100
M5 1:200 1:500
M6 1:300 1:600
M7 1:400 1:800
M8 1:1000 1:2000
Table:Set of Scales

Do not use scales as straight edges to draw straight lines. These are used to draw irregular curved lines in addition to circles or arches of circles.

Category Recommended scales
Enlargement scales 50:1 20:1 10:1
5:1 2:1
Full size 1:1
Reduction scales 1:2 1:5 1:10
1:20 1:50 1:100
1:200 1:500 1:1000
1:2000 1:5000 1:10000
Table: Scales for use on technical drawings (IS: 46-1988)

French Curves:

French curves are available in different sizes. First a series of points is drawn on the desired path and then the most appropriate curve is drawn on the edge of the curve. The elastic curve has a lead bar inside the rubber that bends conveniently to draw a smooth curve through a set of points.
French curves Flexible curves
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