Drawing Instruments and Materials

Drawing is a university language used for communication among technical people. These are engineers, technicians, welders, draughtsmen, etc. We study drawing so that we can draw objects for other people to see and understand what we have in mind without talking to us or asking questions. It is, therefore , important that we learn the language of drawing. To do this, we start with descriptions of instruments and materials that are used , and latter we learn how to use them to produce drawings.

Instruments and Materials for drawing

A good and accurate drawing can only be made through constant practice with the aid of drawing instruments and materials. Below is a list of instruments and Materials for drawing:

1. Drawing Board 2. Tee square 3. Drawing pencil 4. Set of drawing instruments 5.set squares (60° - 30° and 45°) 6. Drawing paper clips or adhesive tape 7. Protractor 8. Scale rules 9. French curves  10. Drawing paper 11. Eraser.

Drawing board

Drawing boards are of two sizes, the half imperial and the full imperial. For a student of technical drawing , half imperial size is most useful as it is idea for the much simpler work that students will be involved in. The half imperial board is 585 x 452 millimeters in size while the full imperial is 812 x 585 millimeters. Ideal drawing boards are made of medium hard even grained hardwood. Quarter sawn obeche wood, with slotted battens on the underside to keep it flat, is recommended for this purpose. The edges of the board should be lined with hard, stable wood like ekki or opepe. Drawing boards can also be made of fine, even grained plywood 12-18 millimeters in thickness, with battens screwed to the underside.

Tee square

The idea tee square is one that is the same size as the drawing board. The tee square is placed on the drawing board with the stock at the left hand edge of the board. It should be handled with care in order not to distort the squareness of the blade with the stock. A suitable tee square is made of mahogany with the square edge lined with a hard wearing wood such as ebony for durability. The stock and blade are best made with quarters sawn wood in which shrinkage and warping are not pronounced.

Drawing pencils

Drawing pencils are of different grades. For technical drawing, a 2H pencil  is ideal for general drawing, while H or HB grades are suitable for lettering. For hand sketching, an H or HB grades pencil, sharpened to a conical point, is suitable, while for technical or engineering drawing, a hard pencil (preferably 2H or 3H) sharpened to a  ' chisel point' would be very useful. A piece of fine emery cloth or No. 0 glass paper would be necessary to keep the points sharp for working to fine limits.

Set of drawing instruments

There are various brands of sets of drawing instruments. A complete sets should contain:

1. A pair of compasses 2. A pair of dividers 3. A bow compass 4. Ink lining lem attachment for compass

An electron compass is ideal, with needle points and adjustment devices, knee joints and extension bars, in addition , a combination set consisting of needle point compasses with ink and pencil divider point attachment, and a pair of bow compasses plus a boe spring pen of  good quality should be adequate for beginners.

Set squares

Set squares play an important role in technical, engineering or geometrical drawing. Wooden or timed iron set squares are of no use, especially when inking on. Acrylic set squares are of great value, and Highly satisfactory with careful use ad the bevelled edges are helpful for inking in. Set squares are used to draw vertical or diagonal lines and can be paired up for specific angle drawing.

Drawing paper clips or adhesive tape

Drawing papers are best held on the boards with the aid of clips PR adhesive tape. The use of pins for holding drawing papers  is regarded as old fashioned , and leads to complaints of ' reaming holes' in paper and board.

Protractor

An idea protractor is made of acrylic material with divisions ranging from half a degree through 90° to 180°.

Scale rules

Scale rules vary considerably in shape. Generally , each edge of the scale rule is graduated , and each designation is marked on the rule. The use of scale rule is vital as most linear sizes are not possible on paper. In theory , it is quite easy to get a map of the world drawn on a sheet of paper while minute parts of a particular engine need to be enlarged for easy reading and clear understanding.

French curves

French curves  are made of acrylic material in which possible curvatures are incorporated. Another type consists of a flexible plastic bar which can be physically bent to suit various curves (known as flexicurve).

Drawing paper

Creamy white paper is idea for drawing. The size vary in relation to the size of the drawing board, usually from quarter to full imperial. For normal class drawing practice, quarter imperial is idea , but in  some cases , paper that Is acceptable. Suitable metric sizes of paper are A2, A3 and A4.

Other Drawing papers

In addition to the normal creamy white drawing paper, there are b: (a) tracing paper, and (b) transparent cloth backed paper

(a) Tracing paper : this is a transparent paper used  for original drawings which are later printed on normal drawing papers. Tracing papers are reference paper for original copies.

(b) Transparent cloth backed drawing paper:

This is used almost the same way as the tracing paper. Valuable documents are usually drawn on cloth backed papers  and they are usually drawn on Cloth blacked papers and they are 'originals'  as against copies for which normal tracing papers is intended. This type of paper is usually used by surveyors.

Eraser

There are various makers of erasers , and they are generally called 'rubbers' . a good eraser must erase cleanly with out picking or tearing the surface of the paper. Most port quality erasers tend to smudge the surface of the drawing paper.

A soft white rubber closely resembling white cheese in colour and structure is idea. It is advisable to draw all lines faintly cleaned up after ink lining. If pencil is desired for the finishing touches , a soft pencil can be used , and later traced with a harder one such as 4H ; then lightly rubbing the eraser over the drawing will remove traces of the soft pencil.

Care of drawing instruments

Just as we need to take care of ourselves , our clothing , pets, houses and any other property, so our drawing instruments also need good care. Therefore , the following precautions should be observed in respect of the instruments:

 Drawing board

1. As far as possible , do not use pins on the drawings board. Use tapes.

2. Do not use the drawing board for any other purpose.

3. When you are not using the  drawing board, you should cover the face with paper or place the board face down.

Tee squares

You should never use the tee square as if it were a walking stick; and further more, never UDR any penknife or blade along the edge of the tee square for any reason. The underside of the blade of the square should be kept clean so that the drawing paper does not get dirty.

Set squares

Do not use any sharp object such as knife or razor blade on the straight  edge of the set square.

Compasses

Never use compass as paper holders

Other instruments

All other instruments should be kept in their packets after use. A cupboard should be made available for complete storage of the drawing boards and all other instruments.