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Tried a 0.005" stepover on a finish pass and the chatter was unreal

I was trying to get a mirror finish on some 6061 and figured a tiny stepover would be perfect. The machine started screaming like a banshee and left a wavy pattern. Anyone got a better approach for super fine finishes without the vibration?
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3 Comments
hill.troy
hill.troy1mo ago
Tiny stepover can actually make chatter worse. It puts too much pressure on a small part of the tool edge. You need a balance. Try a bigger stepover, maybe 0.015", with a very light final depth of cut. Ramp up your spindle speed as high as your machine can handle. A sharp, new end mill is non-negotiable for this. The tool needs to slice cleanly, not push the material around.
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jesse290
jesse2905d ago
Yeah man, I went through the exact same thing on my mill. I was scared to go bigger on the stepover because I thought it would make things worse, but turns out going too small just makes the tool rub instead of cut. I was running like 0.005" stepover and getting this nasty high pitched whine, then I bumped it up to 0.012" and it was night and day difference. Chatter completely went away and the finish was way cleaner. And you're totally right about the sharp tool too, I learned that one the hard way after burning through two end mills trying to push through with a dull one. The whole "light cuts" thing gets repeated too much without people understanding the balance you need.
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kelly.dylan
My old Tormach did the same thing until I switched to a 10% stepover.
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