[Cartel, LLC]

i think i have a chatter problem? i am machining a part that is 5.500" in diamater and 1.375" tall. my tool is a .375" carbide 2 flute with 1.75" loc.
(6061) now, my rough program came out great but when it did the final profile all the way around there is what looks to be chatter marks about halfway down the part. maybe .500" off the bottom and mayb .500" from the top? its only like .375" of ugly machining right in the middle of the part. is my tool dull in that area or ????

[jamesu229]

Probably just the harmonics produced by the combination of a 2 flute endmill, not quite rigid enough setup, and the helix angle of your cutter. Going to a 4 or 5 flute endmill for finish should stabilize this and allow you to increase your feed rate.

[JimBoyce]

Get a shorter End Mill. Also how many flutes are cutting when there is chatter. If 2 flutes are engaged when there is chatter, you may consider making a one flute end milll by grinding away a flute. As Jamesu229 said, increasing the feed rate helps. I do not agree with more flutes, unless it works.