Danger comes from the fact that centrifugal force does not increase in direct proportion to an increase in speed, but instead it increases as the square of that speed increase. When rotational speed doubles, centrifugal force quadruples. This effect means that relatively small changes in speed can produce significant increases in force. In the example mentioned, changing from 6,600 rpm to 7,700 rpm multiplies the speed by 1.167. However, the corresponding centrifugal force would multiply by a factor of 1.167 x 1.167, or 1.36. To take a more extreme example, consider the same wheel with a maximum safe operating speed of 6,600 rpm run on a 5-inch right angle grinder at chicago-pneumatic1 10,000 rpm. This represents an over-speed of about 1.5 times the wheel''s designed speed. But the corresponding centrifugal force-and the corresponding rotational stress on the wheel-would be about 2.3 times as much as the maximum allowed.

One potential source of serious injury in grinding comes from an oversight 2hpbeltsandermodelcp858 that is easy to make: operating the chicago-pneumatic1 wheel in an over-speed condition. While a wheel that is run far enough in excess of its rated maximum speed may shatter within minutes of operation, danger may also result from a wheel run just slightly faster than its rated speed. This less 2hpbeltsandermodelcp858 severe over-speed condition can cause the wheel to be damaged, and the damage may chicago-pneumatic1 result in breakage after further use. For example, operating a reinforced, 9-inch diameter, Type 27 wheel rated for a maximum speed of 6,600 rpm on a 7-inch angle grinder with a speed of 7,700 rpm can cause the wheel to crack. This cracking can lead to breakage later. 2hpbeltsandermodelcp858 Any of these actions sets up a disastrous scenario that could lead to an accident involving serious injury or death.

In short, chicago-pneumatic1 never over-speed a grinding wheel. The speed of the grinder must be compared to the 2hpbeltsandermodelcp858 and chicago-pneumatic1 speed marked on the wheel or package to make sure the machine''s speed is at or below the maximum operating speed of the wheel. Surpassing this rating risks not just wheel breakage but also the safety of shop personnel. About the author: Roger Cloutier is a senior product safety engineer for the Norton Abrasives brand 2hpbeltsandermodelcp858 of Saint-Gobain Abrasives in Worcester, Massachusetts.

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