Tools and Equipment
Tools and Equipment
This domain tests correct selection, safe use, care and calibration of hand tools, measuring instruments and garage equipment. Expect questions on spanner types, torque wrenches, micrometers, vernier calipers, dial gauges, feeler gauges, presses, cranes and lifting gear.
Core rules and concepts
- A ring or box spanner fully surrounds the nut and is preferred for high torque. An open-end spanner gives access but contacts only two flats. An adjustable wrench should not replace the correct size.
- Pull a spanner toward you where possible. Do not use a cheater bar or extend the handle; inspect for cracks and mushroomed heads.
- A torque wrench is a measuring tool. Set it to the specified value, apply steady force and store it at its lowest setting. Never use it as a breaker bar.
- Check a micrometer for zero error, clean the faces and use the ratchet thimble. Read the sleeve plus thimble.
- Vernier least count is one main-scale division minus one vernier division; a common metric least count is 0.02 mm.
- Use feeler gauges for valve clearances and plug gaps without forcing. Use a dial gauge and magnetic base for runout and end play.
- Inspect slings, chains and cranes for safe working load and damage before lifting.
Worked example
A 0.02 mm vernier shows a main-scale reading of 12 mm and the 7th vernier line coincides. Reading = 12 + 7 × 0.02 = 12.14 mm. If the instrument has a zero error of +0.03 mm, the true size is 12.14 − 0.03 = 12.11 mm.
Traps that cost marks
Using an open-end spanner on a tight bolt; extending a torque wrench with a pipe; measuring a hot or dirty part; forgetting zero error; and using a dial gauge without a rigid base.
Key points
- Use the correct spanner size and pull rather than push.
- Torque wrenches need calibration and low-scale storage.
- Vernier reading equals main scale plus coincident line times least count.
- Correct zero error before recording a measurement.
- Inspect lifting gear and know its safe working load.