Manufacturing processes, tools and workshop practice
Manufacturing processes, tools and workshop practice is examined through marking out, cutting, shaping, drilling, joining, finishing, jigs, tolerances and quality control.
Core rules
- Mark out from a datum, a true face or edge, and carry dimensions from it; never stack measurements.
- Use the right saw: tenon/back saw for straight joints, coping saw for curves, hacksaw for metal.
- Drill with a centre punch first; clamp the work; match drill speed to material (slower for metal, faster for wood).
- Jigs hold work or guide tools; templates mark identical shapes; fixtures locate work on a machine.
- Tolerance is the permitted variation; a go/no-go gauge checks it quickly.
- Production scale affects method: one-off uses hand tools; batch uses jigs; mass uses dedicated tooling.
Worked example
Make 20 identical plywood phone stands with a 15 mm slot. Mark one master from a datum edge, cut it, check the slot with a 15 mm gauge, then use it as a template to mark all 20. Clamp blanks in a stack and cut the slot with a router jig, giving +/-0.5 mm. Check the first-off, then every fifth piece with the gauge. If the slot measures 15.4 mm, the cutter or jig has moved; adjust before continuing.
Traps
Measuring each part from the previous part; using a rip saw for a curve; drilling without a centre punch; ignoring grain when planing; checking only the last piece.