Auto and Shop Information
Auto fundamentals
Expect questions on the four-stroke cycle - intake, compression, power, exhaust - and the systems supporting it: fuel, ignition, cooling, lubrication, exhaust, and the drivetrain (transmission, driveshaft, differential, axles). Know the difference between the starting circuit and the charging system (alternator), disc versus drum brakes, and why coolant runs under pressure.
Torque is twisting force; horsepower measures the rate of doing work. A smaller drive gear turning a larger driven gear reduces speed and multiplies torque. The ratio is driven teeth divided by drive teeth.
Shop fundamentals
Know common hand tools and their purpose, measuring tools (tape, ruler, calipers, square), fastener types, and basic wood joints (butt, miter, dowel, mortise and tenon, dovetail). Safety questions favor the conservative option: wear eye protection, unplug tools before adjusting, keep blades sharp, and never leave a chuck key in place.
Traps
- Mixing up the order of the four strokes, especially compression and power.
- Confusing a tap (cuts internal threads) with a die (cuts external threads).
- Assuming a larger driven pulley speeds things up - it slows them down.
- Ignoring coarse versus fine thread pitch on the same bolt diameter.
- Overlooking that a stripped screw head often calls for a screw extractor, not more force.
Worked example
A 12-tooth gear drives a 36-tooth gear. The ratio is 36 / 12 = 3:1, so the driven gear turns one-third as fast and delivers three times the torque. If the small gear spins at 900 rpm, the large gear turns at 300 rpm.
Rule of thumb
For any machine, ideal work in equals work out: force times distance stays constant, so a gain in force always costs distance. On safety items, pick the most cautious answer.