Engineering Drawing and Technical Communication
What this domain tests
Engineering Drawing and Technical Communication tests whether a craftsman can read and produce clear, unambiguous technical information: orthographic views, line conventions, dimensions and tolerances, surface texture, section and welding symbols, title blocks and parts lists. It also tests spoken and written handover-what a fitter must tell the next shift.
Core rules
- Orthographic projection: first-angle places the view from the left on the right of the front view; third-angle places it on the left. Check the projection symbol, not habit.
- Line types carry meaning: continuous thick = visible outline; short dashes = hidden detail; chain thin = centre lines; continuous thin = dimension and extension lines.
- Dimensions state the real size, not the drawing scale. Never scale a drawing for a critical dimension.
- Tolerances: 30 ±0.2 means upper limit 30.2 mm, lower limit 29.8 mm, tolerance 0.4 mm.
- A title block carries drawing number, revision, scale, material, units and approval status. Superseded revisions must be withdrawn.
- Handover notes should state machine or job number, work completed, defects and action required.
Worked example
A drawing gives a bore as Ø25.000/25.021 and a shaft as Ø24.979/25.000. Maximum clearance = 25.021 − 24.979 = 0.042 mm. Minimum clearance = 25.000 − 25.000 = 0.000 mm. The fit is a clearance fit with line-to-line minimum; the shaft may need selective assembly. Reporting about 25 mm is not a valid inspection result.
Traps
Reversing first- and third-angle views; measuring a print with a rule; ignoring revision letters; mixing radius and diameter symbols; and treating general tolerances as exact. Another common loss is a drawing with a missing datum, which makes inspection impossible.