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Grinding stone incident

We have received information of an incident involving a cup grinding stone. In this incident, the cup stone exploded. However, the findings are considered applicable to any type of abrasive wheel.

In the incident, a pipe welder was using a pneumatic grinder to bevel the end of a 3″ pipe when the grinding stone exploded, striking the welder on his shoulder.

The investigation revealed that the guard used on the grind was not the correct one for a cup stone and that the flange was not the correct size for the stone.

The following common errors were identified in the use of grinding stones:

  1. use of flanges of uneven or too small diameter;
  2. use of washers instead of flanges;
  3. flanges without proper clearance or relief;
  4. excessive tightening, causing flanges to bend;
  5. failure to clean all dirt and foreign material from sides of wheels and flanges;
  6. forcing a wheel onto an arbour where fit is tight;
  7. use of any loose washers or bushings to try to make a wheel fit a machine for which it is not intended;
  8. failure to use blotters on wheels.

IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding [email protected] to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.

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IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.