Power tools

Why it matters

Power tools multiply what your hands can do, and they multiply mistakes too. A drill that catches can twist your wrist; a grinder wheel that shatters sends fragments outward at high speed; a frayed cord on a wet slab can electrocute. The fix is mostly routine: inspect before use, set up the work properly, and keep hands and clothing out of the line of fire.

Every site has rules on which tools you may use and when. Use a tool only after you have been shown how, and follow your supervisor's and the manufacturer's instructions.

Power tool families

• Electric (corded or cordless): drills, impact drivers, saws (circular, reciprocating, jig), grinders, sanders.
• Pneumatic: nail guns, impact wrenches, sanders driven by compressed air.
• Powder-actuated: fasteners driven by a charge; operators must be specifically trained and certified by the manufacturer's programme.
• Hydraulic: jacks, crimpers, benders.

Pre-use inspection

Do it every time, before you plug in or insert the battery:

1. Housing: no cracks, missing screws or melted plastic.
2. Cord and plug (corded): no cuts, exposed conductors, taped repairs or crushed sections; ground pin present on three-prong plugs. A double-insulated tool (marked with a square inside a square) has a two-prong plug by design.
3. Battery (cordless): no cracks, swelling or damage; contacts clean. Damaged lithium-ion batteries can catch fire; set them aside and follow the site's disposal rules.
4. Switch: works, and returns to off when released.
5. Guards: present, move freely and return (for example, a circular saw's lower guard).
6. Accessory: bit, blade or disc is the right type, sharp, undamaged and tight. Grinder discs must be rated for the tool's speed (rpm).
7. Chuck key removed before starting a keyed drill.
8. Power supply: on construction sites, corded tools are plugged into GFCI-protected outlets or cords.

If any check fails, tag the tool "Do Not Use" and report it.

Setting up the work

• Clamp the workpiece. Holding a small part by hand while drilling is how hands get hurt when the bit catches.
• Wear the right PPE: safety glasses always; hearing protection for saws, grinders and impact tools; a dust mask or respirator where required (cutting concrete or stone releases silica, which has its own OSHA rules).
• No loose clothing, jewellery or long hair near rotating parts. Avoid gloves near drill bits and chucks.
• Keep the area clear and know where the cord runs.

Using a cordless drill: a worked example

Task: drill a 6 mm hole through a 19 mm pine board.

1. Inspect the drill and battery (above). Fit a 6 mm wood bit and tighten the chuck firmly; tug the bit to check.
2. Set the direction switch to forward and the speed range to the low gear (1) for control. The numbered clutch collar slips at a set torque; for drilling use the drill symbol setting (no clutch).
3. Clamp the board to a bench with scrap wood underneath so the bit exits cleanly and does not hit the bench.
4. Mark the hole with a pencil and an awl dimple so the bit does not wander.
5. Put on safety glasses. Hold the drill with both hands, wrist straight, bit square to the surface.
6. Start slowly, then increase speed; let the bit do the work. Back out occasionally to clear chips.
7. Release the trigger, wait for the bit to stop, set the direction switch to the centre (locked) position, and remove the battery before changing bits.

Rules that prevent most injuries

• Disconnect power (unplug or remove the battery) before changing bits, blades or discs, and before any adjustment.
• Never carry a tool by its cord or yank the cord to unplug.
• Never defeat a guard or tape down a trigger.
• Keep both hands on two-handed tools; keep your body out of the kickback path of saws.
• Let the tool stop completely before setting it down.

Common mistakes

• Using a grinder without its guard, or with a disc rated below the tool's rpm.
• Holding the workpiece in one hand while drilling with the other.
• Wearing gloves near a spinning bit.
• Using a corded tool with a damaged cord because "it still works".
• Leaving the chuck key in the chuck.

Official source

• OSHA hand and power tools: https://www.osha.gov/hand-power-tools

Checked on 2026-10-23.

Recap

• Inspect housing, cord or battery, switch, guards and accessory before every use; use GFCI protection on site.
• Clamp the work, wear eye and hearing protection, keep loose items away from rotating parts.
• Disconnect power before changing accessories.

Try it

The Do tab takes you through a written pre-use inspection of a cordless drill and a supervised practice hole in scrap wood.