SECTION 7.0

The grinding wheel, when carefully and correctly used, is a safe cutting tool. But if it is misused or abused, it does have a very dangerous potential. We know that the rim of a wheel running at 6500 surface feet per minute (SFPM) is traveling at a speed of over 70 miles per hour, thus we can understand how dangerous any grinding wheel can be if it is broken by mishandling or misuse.

Rules and recommendations to maintain the safety of grinding wheel use are listed in this document. This document summarizes knowledge gained from literally thousands of man-hours and decades of practical experience with abrasive tools. This document is recommended for employees involved in the mounting or use of grinding wheels, segments, or mounted points. The safety code referred to herein is the American National Standards Institute (ANSI) standard B7.1.

One requirement of the safety code is a prooftest: all sizable grinding wheels must be overspeed tested by the wheel manufacturer before shipment. Typically, this test stresses each wheel to 2-1/4 times the rotational stress of its maximum usage speed. The test destroys any wheel of substandard strength, so it ensures that all surviving wheels are structurally sound. Hence, a precision wheel is perfectly safe to use immediately after its overspeed test. However, it can become very unsafe if it is cracked, chipped, or gouged after that test. So there is good reason to say that grinding wheels don't break, they are broken.