My rotary grinder bit shredded a $90 flange in 20 minutes

Tried swapping to a cheap rotary burr bit I picked up at a supply house in Gary last Tuesday, thought it would save me time on a tricky weld cleanup. That thing grabbed the metal so hard it walked right off the flange face and tore a groove into the seating surface, boss was not happy when he saw it. I learned the hard way that the angle and the tooth pattern matter way more than the price tag, that bit had way too aggressive of a cut for thin stainless. Now I stick with the carbide bits from the usual catalog and double check the RPM rating before I even touch the grinder. Has anyone else had a burr bit bite them like that, or is it just me being too impatient with the trigger?

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gavinperez28d ago

The part about "walked right off the flange face" really jumped out at me. Nobody talks about how the burr bit's shank length and the collet depth on your grinder changes the leverage. If that bit sticks out too far, even a mild tooth pattern will flex and grab when you lean on it, and that's when it starts dancing all over the part. I had a similar walk-off happen once, and it was because my collet was worn out, not because the bit was cheap. Check that the bit is seated deep and the collet is snug before you blame the cutting edge. A loose setup will make ANY bit act like it's got an attitude problem.