Use of Hand Tools, Measuring Instruments, and Workshop Equipment
This domain tests selection, safe use, care, and correct reading of common shop tools and measuring instruments.
Core rules
- Use the right wrench: box or flare-nut on brake lines, six-point socket on rounded fasteners; never use a screwdriver as a pry bar.
- Torque wrench: set to the specification, pull smoothly to the click, never use it as a breaker bar, and store it at the lowest setting.
- Vernier caliper: reading equals main scale plus vernier; typical least count is 0.02 mm.
- Outside micrometer: least count 0.01 mm; use the ratchet stop and read sleeve plus thimble.
- Feeler gauge: combine blades for the specified clearance; the correct blade drags slightly.
- Dial indicator and magnetic base for runout and backlash; plastigauge for bearing clearance.
Worked example
Vernier: the main scale reads 12 mm past zero and the 7th vernier line aligns on a 0.02 mm caliper. Reading = 12 + (7 × 0.02) = 12.14 mm. Micrometer: the sleeve shows 5.5 mm and the thimble shows 28 divisions. Reading = 5.5 + (28 × 0.01) = 5.78 mm. Reasoning: each thimble division is one hundredth of a millimetre, and the half-millimetre sleeve line must be counted.
Traps
Ignoring zero error; parallax when the eye is not square to the scale; over-tightening a micrometer; using outside jaws for an inside bore; dropping a torque wrench; measuring a hot or oily part.