Miscellaneous Drawing Instruments

1) French Curves

A French curve is a curved ruler used for drawing irregular curves that are neither circles nor circular arcs. It is made of wood, plastic or transparent celluloid. There are different forms and sizes of French curves. French curves are best suited to draw smooth curves/ arcs (which cannot be drawn by a compass) with ease. They are made in various shapes. Some set-squares also have these curves cut in their middle. French curve is free form template make of acrylic and is used to draw a smooth curve passing through a number of points. The outer profile of the French curve is adjusted such the smooth curve passes through more than three points and a curve passing through these lines are drawn. The next part of the curve is then drawn by using the next three points in addition to the last two points of the previous curve. A typical French curve is shown in Fig.1.

Fig.1. French Curve

To draw a smooth curve using French curve first set it by trial against a part of the line to be drawn, then shift it to the next portions. Each new portion should fit at least three points on the curve just drawn. It should be seen that the curve (radius) is increasing or decreasing smoothly and no corner should be formed on the curve.

2) Eraser

An eraser is made of rubber and is used to erase extra pencil work and/or wrongly drawn lines. Soft eraser is the most suitable one for erasing as it leaves a little or no impression on the drawing sheet and it should not spoil the surface of the paper. Frequent use of rubber should be avoided by careful planning.

Fig. 2 Eraser

3) Erasing shield

When, on a drawing, if a part of a line or some lines among many other lines need to be erased or modified, in normal way of erasing will damage the other nearby lines. Erasing shield is a thin metallic sheet having small openings of different sizes and shapes. A suitable opening is aligned to the line to be erased and the line is removed by the eraser.

4) Template

Templates are available for drawing circles, arcs, ellipses, triangles, squares and other polygons. Also, symbols used by various engineering faculties, such as architectural, mechanical, electrical etc. are used in the form of templates. A template is a thin, flat piece of plastic containing various cut-out shapes. It is designed to speed the work of the drafter and to make the finished drawing more accurate. Templates are available for drawing circles, ellipses, plumbing fixtures etc. Templates come in many sizes to fit the scale being used on the drawing.

5) Stencils

A stencil is a thin flat piece of celluloid used to write letters and numerals. This helps the draftsmen to write neatly and uniformly and at a faster rate.

6) Drawing Clips or Drawing Pins and Adhesive Tapes

Both drawing clips and drawing pins serve the same purpose. They are used to fix the drawing sheet firmly in position to the drawing board as one construct the drawing so that it does not shake during preparing drawing. The needle part of the pin is generally made of steel, while the head may be of plated mild steel or brass. Pins of about 15 mm to 20 mm diameter and about 1 mm thick flat heads made of brass are quite convenient, as they do not rust. Pins should be so inserted that the heads sit on the surface of the paper. Clips or adhesive tapes are often used instead of the pins.

Fig.3 Drawing Pins

Fig.4 Drawing Clips

7) Duster or Handkerchief

A Duster or a handkerchief is used for cleaning instruments. It is also used to sweep away the crumps or dusts formed after the use eraser on the drawing sheet. Duster should preferably be of towel cloth of convenient size. Before starting work, all the instruments and materials should be thoroughly cleaned with the duster. The underside of the T-square and the set-squares or the drafting machine which continuously rub against the paper should be frequently cleaned.

8) Drawing Instrument Box

Drawing instruments are generally sold in sets in boxes, but they are also available separately. An instrument box contains the following.

• Large compass
• Large divider
• Bow compasses, bow divider
• Lengthening bar
• Pen point for attachment
• Screwdriver
• Lead case
• Inking pen or liner or ruling pen

9) Roll - N – Draw

It consists of graduated roller, scale of 16 centimeter and protractor. It is ideal for drawing vertical lines, horizontal lines, parallel lines, angles and circles.

Fig. 5 Roll - N - Draw

10) Tracing Paper

It is a thin transparent paper. Figures below it can be seen easily and traced out in pencil ink.

11) Drawing Ink

It is used for making drawings in ink on tracing paper.

12) Clinograph (Adjustable Set Square)

Its two sides are fixed at 90⁰ and the third side can be adjusted at any angle.