Tools, Equipment, and Shop Practices
What this domain tests
Fastener and torque theory, precision measurement, press and bearing work, lifting and rigging, and correct tool selection for heavy-duty repair. Questions often give you a measurement or a torque scenario and ask for the applied value or the wear verdict.
Core rules
- Torque and lubrication: the same bolt needs less torque when lubricated than dry - roughly 20–25% less. Always apply the spec exactly as written (dry, oiled, or thread-locker). Torque-to-yield bolts are tightened to a torque plus a specified angle and are replaced, not reused.
- Torque wrench geometry: a straight extension does not change applied torque; an in-line adapter (crowfoot) does, because it lengthens the lever arm. Correction: setting = spec × L / (L + A), where L is wrench length and A is added length. An adapter at 90° needs no correction.
- Fastener grading: SAE grade 5 (three marks) and grade 8 (six marks); metric class 8.8, 10.9, 12.9. Never substitute a lower grade in a structural or driveline joint.
- Measurement: micrometer for outside diameters, bore gauge zeroed on the micrometer for cylinder bores, dial indicator for endplay and runout, plastigauge for bearing clearance, feeler gauge for valve lash. Always check the tool against a standard before trusting a rejection.
- Bearings and fits: press on the inner race when fitting to a shaft and the outer race when fitting to a housing. Heat bearings in clean oil or an oven, never with a torch.
Worked example
A fastener spec calls for 200 N·m. Your wrench is 500 mm long and you add a 50 mm in-line crowfoot. Setting = 200 × 500 / 550 = 182 N·m. If you set 200, the fastener is over-torqued by about 10%.
Traps
- Ignoring the lubrication state written on the spec.
- Reusing torque-to-yield head bolts or driveline bolts.
- Reading a bore gauge that was zeroed on a worn micrometer.
- Slinging a component off a structural casting edge without a softener or spreader bar.