Materials, Tools, Equipment and Safety Practices
Domain 4 tests material selection for farm-machinery components and the safe choice and use of hand tools, lifting equipment and protective gear.
Core rules
- Engine blocks and housings are usually grey cast iron for damping and castability; crankshafts and connecting rods are forged steel; bushes are bronze or bearing shells with a steel backing.
- Gaskets must match the joint: fibre for water/oil, copper for high temperature, O-rings for dynamic seals.
- Use the correct tool: six-point sockets for hex nuts, box spanners for confined spaces, pullers for bearings; never use an open-end spanner as a hammer.
- Jack stands, not a jack alone, support a machine; chock wheels; lower implements before working underneath.
- PPE for the job: safety glasses, hearing protection, gloves, safety footwear; no loose clothing near PTO shafts.
Worked example
A seized M12 bolt on an exhaust manifold. Reason: heat and corrosion have increased friction. Apply penetrating oil, allow time, use a six-point socket with a breaker bar, and apply heat if safe; avoid a 12-point socket or a pipe extension that can round the head. If it still will not move, drill and use an extractor rather than increasing force until the bolt shears.
Traps
Using a torque wrench as a breaker bar; supporting a tractor on a hydraulic jack only; wearing gloves near a rotating PTO; choosing mild steel for a high-wear bush; mixing incompatible coolants.