Grinding stone incident
- Safety Flash
- Published on 1 July 2001
- Generated on 18 November 2025
- IMCA SF 07/01
- 1 minute read
We have received information of an incident involving a cup grinding stone.
What happened?
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:
- Use of flanges of uneven or too small diameter.
- Use of washers instead of flanges.
- Flanges without proper clearance or relief.
- Excessive tightening, causing flanges to bend.
- Failure to clean all dirt and foreign material from sides of wheels and flanges.
- Forcing a wheel onto an arbour where fit is tight.
- Use of any loose washers or bushings to try to make a wheel fit a machine for which it is not intended.
- Failure to use blotters on wheels.
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