Hand Tools
Domain 5 tests identification and correct use of hand tools: which wrench for which fitting, how to apply force safely, and how to keep cutting edges and jaws in working condition.
Wrenches and spanners
- Pipe wrench (Stillson): serrated jaws bite the pipe; pull the handle towards you with the jaw opening facing the direction of turn; never add a cheater bar.
- Chain and strap wrenches grip polished or plastic pipe without marking it.
- Basin wrench reaches tap backnuts behind a basin; adjustable and ring spanners suit nuts and unions.
- On a union, use two wrenches opposed: one holds, one turns.
Cutting and striking tools
- Hacksaw: 18 TPI for thick or soft metal, 24 to 32 TPI for thin wall; use the full blade with steady strokes.
- File and reamer remove burr; a cold chisel is struck with a club hammer only.
- Plunger and drain auger clear blockages; try the force cup before chemical cleaners.
Worked example
A 25 mm GI union will not open. Reasoning: apply penetrating oil, hold one side with a pipe wrench and turn the other with a second wrench in the opposite direction, pulling both handles towards you. Gentle heat may help a steel joint, but never near plastic or a solvent joint. A cheater bar is avoided because it distorts the pipe and can snap the jaws.
Traps
Using a pipe wrench on chrome or plastic fittings; hammering a wrench; using an adjustable spanner as a hammer; cutting towards your body.