Hand Tools
What this domain tests
Hand Tools tests selection, condition, and technique for files, saws, taps, dies, reamers, scrapers, punches, wrenches, and assembly tools. The exam focuses on whether the tool matches the material and task, and whether the method protects the tool and the workpiece.
Core rules and concepts
- Files cut on the forward stroke. Use a single-cut file for finishing and a double-cut file for rapid stock removal; clean the file with a file card, and never use a file without a handle.
- Hacksaw blade pitch must suit material thickness: fine pitch for thin tube and sheet, coarser pitch for solid bar. At least three teeth should be in contact with the work.
- Tap drill size for a unified thread is approximately major diameter minus one pitch. Use the correct cutting fluid, start the tap square, back off to break chips, and never force a dull tap.
- Hand reamers remove a small amount of material and must be started aligned; turn them in the cutting direction only, and do not reverse a hand reamer.
- Scrapers are for bearing and fitting work, not for removing large amounts of metal. Mark the high spots with bluing and scrape only those points.
- Wrenches must fit the fastener flats; use a torque wrench where specifications exist, and avoid cheater bars.
Worked example
Select a tap drill for a 3/8-16 UNC thread. Major diameter = 0.375 in; pitch = 1/16 = 0.0625 in; tap drill = 0.375 − 0.0625 = 0.3125 in, which is 5/16 in. Reasoning: the minor diameter must leave enough material for the tap's threads but not overload the tap. A 5/16 in drill is the standard choice for 3/8-16 in mild steel.
Traps that cost marks
Using a dull file and polishing the work instead of cutting; choosing a coarse blade for thin-wall tube; starting a tap with a taper tap but no alignment; reversing a hand reamer; and using an adjustable wrench on a precision hex. Tool condition is part of the answer.