Tools and Equipment
Domain focus
Tools and Equipment tests selection, safe use, care, and measurement reading. Expect hand tools, sockets, torque wrenches, micrometers, vernier callipers, feeler gauges, lifting equipment, and workshop machines.
Core rules
- Use the correct size and type: a spanner must fit the nut flats fully; never extend a spanner with a pipe to increase leverage.
- A torque wrench tightens to a specified value and is not used to loosen fasteners. Follow the service manual and reset it after use.
- Vernier least count = main-scale smallest division / number of vernier divisions. Micrometer least count is usually 0.01 mm.
- Check zero error before measuring; read square to the scale to avoid parallax.
- Keep measuring faces clean, lightly oiled, and stored in a case. Do not drop them or use them as hammers. Use a proper puller for bearings; do not hammer shafts.
Worked example
A vernier has a main-scale division of 1 mm and 50 vernier divisions, so least count = 1/50 = 0.02 mm. The main scale reads 12 mm and the 24th vernier line coincides. Reading = 12 + (24 × 0.02) = 12.48 mm. The multiplication converts vernier divisions into millimetres.
Traps
Reading the wrong scale, ignoring zero error, using an adjustable wrench on a tight bolt, and applying torque without a smooth pull are frequent errors.