Technical drawings, graphic images and sketches can be created using a variety of instruments, ranging from traditional tools such as pencils, compasses, rulers and a variety of triangles as well as by computer. Drawing tools are used to make accurate and legible drawings and models. Whilst the computer can be used for most drawing and modeling requirements today, traditional drawing instruments such as those mentioned above are still important very important, particularly for freehand sketching and experimenting with shapes and lines. When drawing, sketching or attempting basic graphics work the pieces of equipment shown below are very useful and often essential.
A protractor is used to measure angles. A typical protractor is a semi-circular piece of plastic with 180 degrees printed around its curve. This piece of equipment is not only used in graphics for constructing accurate drawings but is also used in subjects like Mathematics. Also available for graphics is a full circle protractor which can be used to accurately measure angles greater than 180 degrees.
A Mechanical pencil (sometimes known as a clutch pencil or refillable pencil) are used in drawings such as Orthogonal or Isometric drawings as they provide a very constant line thickness. The pencils come in a number of line thicknesses with the more common being 0.35, 0.5, and 0.7. These pencils can be very expensive as are the refills. (Diagram 2)
A compass (diagram 3) (or pair of compasses) is a technical drawing instrument that can be used for drawing circles or arcs. As dividers, they can also be used as tools to measure distances, in particular on maps. Compasses can be used for mathematics, drafting, navigation, and other purposes.
Compasses are usually made of metal and consist of two parts connected by a hinge. One part has a spike at its end which stops it from sliding on the paper when drawing a circle or arc, and the other part a pencil. The distance between the legs can be adjusted to allow the changing of the radius of the circle drawn.
Set Squares are used to draw accurate angles. The most common set squares are 45 degrees and 60/30 degrees. When using set squares they should always be used along with a T-Square. The Set-square rest on the straight edge of the T-Square and this ensures that the angle is drawn straight and with accuracy.
A ruler is one of the most important pieces of drawing equipment. An opaque-type rulers should only to used to measure distances with lines being drawn with T-Squares and Set Squares. But it must be remembered that the edge of a ruler is not guaranteed to have a perfectly straight edge unlike a good T-Square or Set Square. Rulers used in technical drawing are usually made of polystyrene. Rulers come in two types according to the design of their edge. Straight edge can be used with lead and felt pens, whereas when technical pen is used the edge must be grooved to prevent the spread of the ink.
An eraser such as Staedtler Mars Plastic Erasers, (sometimes called a rubber), is an item used to remove the marks left by pencils on your drawings. They can also be used to remove some types of pens. They are often used with the aid of an erasing shield. Modern erasers come in a variety of colours, and may be made of rubber, vinyl, plastic, gum, or similar materials. Erasers work by pick up graphite particles from the paper. The molecules in erasers attract the graphite from the paper thus removing it. The English engineer Edward Naime is credited with the invention of the eraser in 1770.
A French curve is a template which is generally made out of plastic and is composed of many different curves and are normally purchased in a set of three or four (Diagram 7). They are used in manual drafting to draw smooth curves of varying radii. The shapes are segments of the Euler spiral or clothoid curve. The curve is placed on the drawing material, and a pencil is traced around its curves to produce the desired result.
A flexi-curve, also known as a flexible curve or flex curve is a flexible drawing tool that can be moulded to almost any curve or contour. It is usually made from lead which is wrapped in steel ribbons and covered in flexible plastic or rubber. They are used to draw curves such as lines connecting points on a pattern.
An Ellipse template is used for drawing ellipse or oval shapes accurately. Diagram 9 shows 30/60 ellipse template. It is particularly useful for drawing ellipses on isometric drawings.
A circle template is used to draw circles of set diameters. They are particularly useful if the circle is to small to be able to use a compass. They are plastic with a number of accurate circles cut out. The circle template has its centers indicated at the edge of the circle. These are used to assist in locating the template accurately on your drawing. The diameter is selected and a sharp pencil is used to draw the circle or arc.
A drawing board is a flat, smooth board on which to attach paper for making drawings or designs. Traditionally they are made of timber however modern day boards are constructed out of plastic. The board can be purchased in A4 size although they are more commonly found in schools as an A3 size format.
Board clips are used to hold the drawing paper in position when drawing board is not available. They are designed to clip on to the edge of a table or portable timber board and hold the paper down firmly against the flat surface. (Drawing board or table)
The eraser shield is a simple metal or plastic plate, with openings of different sizes and shapes. These openings allow precise masking of small areas which allows you to erase without smearing or the accidental erasure of surrounding areas. An eraser shield is useful when correcting and editing a drawing.