Lettering
What the exam tests
Lettering tests legible single-stroke capital lettering and numerals, guide-line use, uniformity, and correct height and spacing. Questions may ask for standard heights, stroke order, vertical or inclined capitals, and the difference between lettering for titles and dimensions.
Core rules
- Use capital letters for technical lettering; lower-case is not normal on engineering drawings except in notes where permitted.
- Standard heights are 2.5, 3.5, 5, 7, 10, 14 and 20 mm. Choose a height that remains legible after reproduction; never mix heights in one word.
- Draw light guide lines for cap height and baseline with a 2H pencil, then letter with HB or B. Keep strokes single-stroke and uniform.
- Vertical strokes should be truly vertical; inclined lettering usually uses a slope of about 75° to the horizontal.
- Space letters optically: more space between round letters, less between straight strokes. Words should not touch.
Worked example
To letter TECHNICAL at 7 mm cap height, draw two horizontal guide lines 7 mm apart. Mark the word width lightly, allowing about 5 mm between letters. Draw T and E with horizontal strokes first, then vertical stems. Keep H and I strokes parallel and the C and G curves open. Check the word as a whole; adjust spacing rather than letter height.
Traps
Freehand lettering without guide lines produces wandering baselines. Heavy pencil pressure closes small counters in A, R and 8. Do not use lower-case or decorative styles. Dimension numerals must be clear enough to read at the drawing's final scale; cramped spacing is a common mark loser.