Drawing and Design: notes

Lines and layout

• Line types: a continuous thick line shows outlines you can see. A thin dashed line shows hidden detail. A thin chain line (long and short dashes) shows a centre line. Thin continuous lines are used for dimension lines and projection lines.
• Lettering: use clear capital letters of one height so the drawing is easy to read.
• Scale: a scale of 1:5 means the drawing is five times smaller than the real object. A 1000 mm table top is drawn 200 mm long.

Views

• Orthographic projection: shows an object as flat views from the front, side and top, lined up with each other. In first angle projection the plan sits below the front view. In third angle projection the plan sits above it.
• Isometric drawing: a pictorial view with the sloping lines drawn at 30 degrees to the horizontal.
• Oblique drawing: the front face is drawn true shape and the depth lines run back at 45 degrees, often at half length.
• Sectional view: shows the inside of an object as if it were cut, with hatching on the cut surface.

Design and planning

• Design process: identify the problem, write a brief, research, sketch ideas, choose one, make a working drawing, make it, then evaluate it.
• Dimensioning: give sizes once, in millimetres, with the unit left off.
• Cutting list: a table of each part with its name, quantity and length, width and thickness.