Finally got a tricky deep pocket finish to work on a 316 part

I had this job for a customer in Portland, a small run of 316 stainless parts with a deep, narrow pocket that needed a mirror finish. My usual method with a long end mill was leaving chatter marks no matter what speeds I tried. After two scrapped parts, I remembered something an old timer told me about using a boring head for finishing, not just sizing. I set up a boring bar with a tiny radius insert, ran it at a super low feed, like 2 inches per minute, and just let it skim. It took forever, but the finish came out perfect. I was honestly shocked it worked that well. Has anyone else tried using a boring head for finish work on tough materials?

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3 Comments

joseph_torres5mo ago

Can't believe you got a mirror finish on 316.

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the_zara5mo ago

What mirror finish? I just got lucky with the light and a lot of polishing compound. It looks good from across the room.

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troy_bennett905mo ago

Man, I always thought boring heads were just for hitting a size. Never crossed my mind to use one for a finish pass. Your story makes total sense though, that light skim is the key. I might have to try that next time I'm fighting chatter in a deep slot.

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