Safety advice when using angle grinders

Used correctly, assessing potential risks and hazards, and with appropriate PPE, discs used on angle grinders can be highly efficient and safe for the purpose for which they were designed.

Operators of angle grinders should always check the following:

  • When changing a disc on an angle grinder the angle grinder has been isolated from its power source.
  • Suitable personal protective equipment (PPE) is worn during use.
  • The spindle speed of the angle grinder does not exceed the maximum operating speed of the disc in revolutions per minute. (RPM).
  • The angle grinder should be checked for safety. Including guard, retaining nuts ,switch, electric cable, plug, spindles and handle and if pneumatic, couplings and hose. Any damage parts should be replaced prior to use. Excessive vibration may indicate worn bearings that may create instability in the disc. Remove grinding debris that may have settled on the guard as this may come loose during use.
  • Check for any damage to the disc such as chips, cracks, warping or contamination. Destroy damaged discs.
  • Only use discs that are designed for the purpose indicated on the disc. If in doubt seek advice.
  • When using type 41 (Flat cutting discs), type 42 (depressed centre cutting disc) or type 27 depressed centre grinding disc) check the use by date has not been exceeded. This is usually found on the metal reinforcement around the bore of the disc.
  • The disc should sit on the base flange of the angle grinder securely. Depressed centre discs are designed so that the disc is raised above the base of the guard.
  • Diamond cutting blades have a rotational direction that must be aligned with the direction marked on the angle grinder.
  • When replacing the retaining nut do not over-tighten as the disc will tighten to the spindle on start up. Over-tightening may crack the disc. Special care should be taken when securing the retaining nut, with the use of a pin spanner, to thin cutting discs.
  • Rotate the disc by hand to make sure it does not come into contact with the guard.
  • Adjust the guard to be between the operator and the disc. This is important as the guard will have to be adjusted to a position suitable for either cutting or grinding.
  • Allow newly mounted discs to run at operating speed, with the guard in place, for a reasonable time before commencing cutting or grinding. During this test no person should be in line with the opening of the guard.
  • The operator should consider the proposed working area and carry out a thorough risk assessment prior to starting the angle grinder.

More safety advice

  • Always handle and store discs and wheels carefully. Cutting discs should be stacked horizontally or flat. Depressed centre discs should be placed on top each other or stored in the original packaging. Store discs away from damp atmosphere and extreme temperatures.
  • Check conformity to the respective standard of the product used. EN12413 for bonded abrasive (type 27,41 and 42 discs). EN13236 for superabrasives (diamond blades). EN13743 coated abrasives (flap and fibre discs).
  • Consider using discs marked with OSA logo. The Organisation for the Safety of Abrasives.
  • Always secure the work-piece firmly while it is being cut or ground.
  • Always use the angle grinder in a comfortable position, where the work-piece is well balanced and the angle grinder is well supported.
  • Grind at an angle above 30 degrees to the work-piece with a depressed centre grinding disc.
  • Keep the working area clear to avoid operator trips or falls. Special care should be taken with electric leads and air hose.
  • Never use a damaged discs. Destroy damaged discs.
  • Never force a disc on to a machine spindle.
  • Never use an angle grinder in poor condition.
  • Never use an angle grinder without its guard.
  • Avoid applying side pressure to a cutting disc.
  • Never try to stop a disc by applying pressure to the periphery of the disc. Always switch the machine off and allow the wheel to stop revolving.
  • Do not allow the disc to be trapped or pinched in the cut.
  • Do not apply excessive pressure onto the disc so that the driving motor slows down.
  • Never grind on the side of a cutting disc.
  • Never attach more than one disc to machine.
  • Do not drop or lower an angle grinder by the cable or airline onto the floor. A disc can be easily cracked, if it is put down hard, by the weight of the machine. This is a common cause of disc breakage.
  • Always use an angle grinder with both hands with the handle in place.

More on training in the safe use of abrasive wheels and discs.

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