1.3.1: Tools
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Drafting tools are needed to lay out the different shapes and lines used to create drawings and sketches. Basic knowledge of the available tools and how to use them will assist you in your drawing.
Drafting board or table
The drafting board is an essential tool. Paper will be attached and kept straight and still, so the surface of the drafting board must be smooth and true, with no warps or twists. The surfaces of most drafting boards are covered with vinyl because it is smooth and even.
The drafting board or table should have two parallel outside working edges made of either hardwood or steel.
Most drafting table tops can be set at different heights from the floor and at any angle from vertical to horizontal. Other drafting tables may not have the same adjustments and may be limited to being raised only from horizontal to a low slope.
To reduce back strain, use an adjustable drafting stool when working at a drafting table. Tables or boards should be a minimum of 1.2 m (4 ’ ) in width and 0.9 m (3 ’ ) in height.
T-square
The fixed head T-square is used for most work. It should be made of durable materials and have a transparent edge on the blade. To do accurate work, the blade must be perfectly square and straight, which should be checked regularly.
The T-square is used to draw horizontal lines and align other drawing instruments. If you are right-handed, you hold it tight against the left edge of the drawing board and move it up and down as required. When you make close adjustments, your fingers should be on top of the square, and you should use your thumb to control the T-square’s movement, Figure \(\PageIndex{1}\).
When drawing horizontal lines, incline your pencil in the direction you are drawing the line. Hold the pencil point as close as possible to the blade. Roll the pencil between your fingers to prevent the point from becoming flat on one side.
Triangle
A triangle (set-square) is made of clear plastic. Some triangles have rabbeted edges (Figure \(\PageIndex{2}\)) so that when you draw lines, the corner of the edge is set away from the paper to help prevent smudges and ink blotches.
Protractor
Drafting machine
Drawing pencils
Erasers and erasing shields
Templates
French curves and splines
Compass
A compass can be used for drawing circles, bisecting lines, or dividing angles. For very large circles, you can use a beam compass. The four types of compasses are shown in Figure \(\PageIndex{12}\) — Figure \(\PageIndex{14}\). Most compasses can be fitted with leads, pens, or points.
When using the compass, tilt it in the direction of the line, as shown in Figure 13
Dividers
Dividers (Figure \(\PageIndex{16}\)) are used for transferring dimensions from a drawing to a measuring device such as a ruler or scale. They are also used when scribing directly on material like metal.
Dusting cloth or brush
It is essential to keep your drawings and drafting surface clean. When equipment gets dirty from the lead pencils, you should clean it regularly so that it does not smudge your drawings. Any soft, clean cloth is suitable. You may want to wash your board occasionally with a spray cleaner.
Use a brush like the one in Figure \(\PageIndex{17}\) to clean your table before placing paper down and sweep away any debris as you draw. If you use your hand to brush, you could leave marks on the paper. After sharpening a pencil, wipe off any dust clinging to the pencil’s point to prevent smudging.
Scale rulers
Scale rulers let you draw diagrams at a reduced scale. They also let you obtain dimensions from a scaled drawing. Scale rulers come in various types to meet the requirements of many kinds of work. Most scale rulers have three edges and six different scales. The scales are read from either end of the rule. A typical combination of metric scales is 1:20, 1:50, 1:100, 1:25, 1:75, and 1:125.
Because of the decimal basis of metric measurements, metric scale rulers are both applicable and easy to use at any scale. Figure \(\PageIndex{18}\) shows the two scales from both ends of the same side.
Imperial scale rulers may be an architect’s ruler, a mechanical engineer’s ruler, or a civil engineer’s ruler (Figure 17). The architect’s scale ruler is the most common and is in inches and fractions of inches. A mechanical engineer’s scale ruler comes in inches and decimals of inches. A civil engineer’s scale ruler comes in feet and decimals of feet.