Aluminum Oxide Grinding Bits | McMaster-Carr
The abrasive grains in these bits are blended with rubber, which cushions during grinding to produce a smoother surface texture than other bits with similar grits.. Bits for steel are aluminum oxide, which is the most common abrasive used in grinding metal.. Caution: As bit shank is exposed beyond 1/2 ", maximum safe rpm decreases significantly. Refer to ANSI standard B7.1.