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Alert 17 - Angle Grinders

This alert highlight the risks associated with removing guards and using incorrect discs on angle grinders.


In early February 2016, a Queensland worker received fatal injuries while operating a 230 mm angle grinder. The worker was killed when part of a broken disc struck the worker’s chest causing fatal injuries.

Safety issues

Power tools must be operated and maintained in accordance with the manufacturer’s instructions.  Where guards are provided they must be used on all power tools since guards reduce the risk of the tool injuring the worker. In the case of angle grinders a properly fixed guard prevents:

  • broken pieces of the disc hitting the worker
  • the worker’s hand contacting the moving blade, and
  • blade damage from the weight of the grinder resting directly on the disc when not in use.

Cutting discs are generally designed for a maximum outside edge speed where:

  • larger angle grinders are manufactured with lower revolutions per minute (RPM) speeds than smaller angle grinders, and
  • fitting a larger disc to a smaller angle grinder will increase the edge speed excessively where the disc may shatter striking the worker with considerable impact or others in the vicinity.

Control measures

Duty holders must adopt measures that address the risk posed by the use of power tools, with regard to angle grinders these measures will include:

  • using the angle grinder with the correct guard that is supplied by the manufacturer
  • fitting the right sized disc matching the spindle flange
  • using the tightening tool supplied by the grinder manufacturer to tighten the disc. The use of another device (i.e. punch and hammer) can damage the disc and grinder
  • holding the angle grinder with both hands ensuring the side handle is inserted on the side of the unit that gives the best grip for the work activity
  • using the correct disc for the nature of the task. Grinding with a cutting disc damages the disc and increases the likelihood of the disc breaking during use
  • ensuring the maximum RPM disc speed marked on the disc is higher than the maximum speed of the angle grinder
  • ensuring damaged or suspect discs are disposed of and not re-used
  • allowing the grinder to run to speed before cutting or grinding
  • providing appropriate training and supervision consistent with the nature of the work task, and
  • ensuring workers use appropriate personal protective equipment and that exclusion zones are enforced where the nature of the work task increases the risk to third parties in the vicinity.

Further information

Model Code of Practice – How to manage work health and safety risks

Model Code of Practice – Managing Risk of Plant in the Workplace

This Alert was developed from material supplied by and is reproduced with the courtesy of WorkSafe QLD.


Page last updated: 08 Apr 2016