Grinding and cutting safely The FABRICATOR
Never exceed the maximum RPM rating indicated on the wheel. For example, a 4 in. wheel rated at 9,000 RPM should not be used on a 4 in. grinder with a noload speed of 10,000 RPM (typical for a 4 in. grinder). Many people remain under the impression that it is the loadoperating speed that cannot be exceeded. This is simply not the case.