Workshop Safety, Hand Tools, Special Tools and Measuring Instruments
What the exam tests
This domain tests the habits and instruments a technician uses around every job: personal protection, workshop housekeeping, correct use of hand and special tools, and accurate measurement with vernier, micrometer, dial gauge and torque wrench.
Safety rules that are examined
- Fuel, solvent and battery-charging areas need ventilation and no open flame; a lead-acid battery on charge releases hydrogen.
- Lift a two-wheeler under the frame or sump with the stand stable, and chock the opposite wheel before removing a wheel.
- Disconnect the negative terminal first and reconnect it last, so the spanner cannot short to the frame.
- Never blow brake dust out with compressed air; use a vacuum or a damp cloth.
- Wear eye protection when grinding, and keep loose sleeves away from a rotating wheel or chain.
Hand tools and torque
Spanners must be a snug fit; a 13 mm ring on a 12 mm hex rounds the flats. Sockets are pulled, never hammered on. A torque wrench is a measuring instrument: work in the middle of its scale, tighten in a diagonal pattern in stages, and never use it to loosen. Small-engine cylinder head bolts are typically 8-12 N·m in stages; axle nuts 50-80 N·m.
Special tools and instruments
Clutch holder, flywheel puller, valve spring compressor, bearing puller, seal driver, chain rivet tool. Measuring: vernier least count 0.02 mm, outside micrometer 0.01 mm, dial gauge 0.01 mm, feeler gauge for valve clearance, plastigauge for bearing clearance.
Worked example
A 0-25 mm micrometer shows 5.5 mm on the barrel and 28 divisions on the thimble: 5.50 + 0.28 = 5.78 mm. If the valve stem standard is 5.975-5.990 mm and the service limit is 5.90 mm, the stem is worn and the valve is replaced. The reading and the limit are written on the job card.
Traps
Reading a vernier from the wrong zero, ignoring micrometer zero error, using a torque wrench as a breaker bar, measuring a hot engine, and mixing imperial and metric feeler blades.