Tried a 4-flute end mill on aluminum and got chatter city

Last week I swapped my usual 2-flute for a 4-flute on a 6061 job, thinking it would give a better finish. Ran it at the same speeds and feeds I normally use, and the surface came out looking like a washboard. Learned that aluminum likes more flute clearance and I should've bumped up the RPM and lowered the chipload. Has anyone else made that mistake or do you stick to 2-flute for softer metals?

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emma_baker615d ago

My buddy did the exact same thing last year on a job for a local shop. He ran a 4-flute on some 6061 and it sounded like a angry bees nest. He said it took him forever to figure out he just needed to drop the feed and let the tool spin faster. Now he jokes that 4-flutes are for steel and 2-flutes are for anything that machines like butter.