Maximum operating speed tables for A, B and W shapes are published in ANSI B7.1 Safety Guide for the Use, Care and Protection of Abrasive Wheels. Copies of ANSI B7.1 may be ordered from the Unified Abrasive Manufacturers’ Association, 30200 Detroit Road, Cleveland, Ohio 44145-1967.

Causes of Grinding Wheel Breakage

Here is a list of some of the causes of grinding wheel breakage.

  • Wheel damaged during transportation. Inspect all grinding wheels before using them.
  • Machine speed higher than recommended RPMs. Consult ANSI B7.1.
  • Lack of knowledge and training. If you do not know how to use a grinding wheel, get help from someone who does.
  • Grinding on the wrong surface of a grinding wheel.
  • Operator carelessness. Any grinding wheel can be broken if not used properly.
  • Improper mounting of grinding wheel. See ANSI B7.1.
  • Sudden forcing of the wheel into your work piece.

Sandusky Chicago Abrasives Wheel supplies a Safety Guide with each box of mounted wheels. Operating mounted wheels higher than the maximum safe operating speed may result in failure of the mandrel. 
Every mandrel - mounted wheel - overhang combination has a certain speed at which vibration due to deflection or whip becomes excessive. This speed varies with the dimensions of the wheel, diameter of the mandrel and the overhand, which is distance between the mounted wheel and the power tool chuck or collet.

The maximum speed is not measurably affected by the type or style of machine used. However, the condition of the machine spindle, bearings and chuck will affect the safe maximum speed. Also important are care in mounting the wheel as well as run-out and unbalance of the wheel.