ben_nguyen•11d agoMost Upvoted

Picked a 2 flute end mill over a 4 flute for that aluminum job last week

I was getting bad chatter on some 6061 parts for a customer in Portland. Had to choose between a 2 flute and a 4 flute .25 inch end mill for a deep slot. Went with the 2 flute because the chip clearance is way better at lower RPMs. Worked out smooth no vibration and the finish came out good has anyone else switched flutes mid job and seen a big difference?

2 comments

2 Comments

william_carter10d ago

Actually you mentioned "lower RPMs" and that is the part I want to touch on. A 2 flute end mill generally will let you run a higher RPM than a 4 flute because it has less cutting edges per revolution. If you were getting chatter at lower speeds, it might have been more about your feed rate or maybe the machine's rigidity rather than the flute count. I've seen plenty of guys run a 4 flute just fine at a higher RPM with a lighter cut and get a stellar finish. Not saying your choice was wrong because the chip clearance on a deep slot in 6061 is definitely a real concern. But I would double check your speeds and feeds before you commit to one flute count over the other. That chatter could have been fixed with a different DOC or a climb cut.

joseph_adams6610d ago

Yeah I had a similar issue a while back cutting some 6061 slots on my little Bridgeport. I was running a 4 flute and getting that chatter no matter what I did with the feed. Swapped to a 2 flute and it was night and day better. But honestly I think part of it was the machine itself just doesn't have the rigidity for a 4 flute at the speeds I needed to rough with. For finishing passes though I've had good luck with a 4 flute and a climb cut at like 0.010 doc, really smooth. So for me it really depends on the operation and how deep I'm going.