Machines, Equipment and Power Tools
This domain tests safe and correct use of shearing machines, press brakes, slip rolls, drills, grinders, nibblers and power shears. Questions often combine a calculation with a safety decision.
Machine use and safety
- A guillotine shear has a hold-down, back gauge and guard. Never place hands near the blade; use a push stick for short pieces. Set the back gauge from the machine datum and check the first cut.
- A press brake needs correct punch, die and tonnage. Do not exceed the rated tonnage, and keep hands out of the die area; use light curtains or two-hand controls.
- Slip rolls have pinch points. Adjust the roll gap with the machine stopped and the power isolated. Power tools must have intact cables, correct guards and a residual current device where available.
Worked example
A 10 mm high-speed steel drill is to drill mild steel at a cutting speed of 25 m/min. Spindle speed N = 1000V/(πD) = 1000 × 25/(π × 10) = 796 rpm. Set the drill press to about 800 rpm, use coolant, and clamp the work. Reasoning: larger diameter or harder material requires lower spindle speed to keep the cutting-edge temperature under control.
Traps that cost marks
Overspeeding a drill or grinding wheel; removing a guard for a short job; adjusting rolls while they turn; and using a cracked or incorrect grinding wheel.