Produce a working drawing with views and dimensions, using a sensible scale so the product can be made

What this dot point is asking

SEAB wants you to produce a working drawing: an accurate drawing with the right views and full dimensions, drawn to a sensible scale, so that someone could actually make the product from it. Where a pictorial sketch explores an idea, a working drawing is the precise instruction for making. The skills are showing the views, dimensioning clearly, and using a scale correctly.

The answer

What a working drawing is for

A working drawing is the final, accurate drawing used to make the product. It must contain enough information that a maker who has never seen your idea could build it to the right sizes. That means clear views, complete dimensions, and a stated scale.

Orthographic views

A working drawing usually shows the object in flat orthographic views, looking straight at it from different directions:

• the front view,
• the side (end) view,
• the top (plan) view.

Each view shows the true shape from that direction. Together they describe the whole object without the distortion of a 3D sketch.

Adding dimensions

Dimensions are the sizes written on the drawing. Rules of thumb:

• give every size needed to make the product, and avoid repeating the same size twice;
• place dimension lines outside the view with small arrows and the measurement;
• use millimetres consistently.

A working drawing without dimensions cannot be made accurately, so dimensions are essential.

Using a scale

Large objects will not fit full size on paper, so you use a scale. A scale of 1 to 3 means every 1 unit on paper represents 3 units in real life, so the drawing is smaller but in correct proportion. To find a drawing size, divide the real size by the scale number; to find a real size, multiply. Always state the scale on the drawing so sizes are not misread.

Examples in context

Example 1. A flat-pack stool. The maker draws front, side and top views with every size dimensioned and the scale stated, so the parts can be cut to length accurately from the drawing alone, without seeing the original idea.

Example 2. Choosing a scale. A 1200 mm bookshelf will not fit on paper full size, so the student draws it at 1 to 5, giving a 240 mm drawing in correct proportion, with the scale clearly noted so no one builds it five times too small.

Try this

Q1. Name the three orthographic views usually shown on a working drawing. [3 marks]

• Cue. Front view, side (end) view, and top (plan) view.

Q2. A real part is 450 mm long. At a scale of 1 to 3, how long is it on the drawing? [2 marks]

• Cue. 450 divided by 3 = 150 mm.

Q3. Explain why a working drawing must include dimensions and a stated scale. [3 marks]

• Cue. Dimensions give the exact sizes needed to make the product, and a stated scale lets the maker read those sizes correctly from a drawing that is smaller than the real object.