I finally figured out why my finish pass kept glazing

Spent three hours last night chasing a rainbow finish on some 6061, turns out I was running too many RPMs for the insert geometry. Anybody else ever get humbled by a simple speed/feed chart they skipped?

2 comments

2 Comments

jones.anna29d ago

What insert geometry were you running? I got burned by the same thing on an older CNMG432 that was meant for stainless, ended up with a mirror finish that looked great until I measured it and realized I'd work hardened half the part surface.

drewsullivan29d ago

Wait, you got a mirror finish out of an old CNMG432 that was meant for stainless? I had the exact same thing happen with some 304 I was roughing out. Thought I was finally getting the hang of it, mirror shine on the outside, feeling like a pro. Then I chucked it up to bore out the center a few days later and that stuff was harder than a coffin nail. Total nightmare, had to scrap the part and redo the whole thing from scratch with a fresh bar.

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