Can't Stop the Squealing!

[Thumb]

I'm on my second lower and even through the 1st one I can not get the dang thing from squealing no matter the feed speed, the bit speed, or how little I take off. it just squeals like crazy. Is it the 4-flute bit or something else. I'm using kerosene as a lubricant/coolant if that matters. I'm pretty sure the lower is 6061 but it could be 7075. It does not do it if I just plunge. BTW, I'm pretty new at milling but have done it for years at work, someone else just set it up and I ran it.

[dallen]

can't help with the squealing, but the parts your working on should be 7075.

[EdK]

Is it a billet lower of a forged lower?

Ed

[Thumb]

It's a billet. I'll see if I can find out for sure if it's 6061 or 7075.

[Dr Stan]

Are you plunge cutting?  If so make sure you use a center cutting end mill.

Or is the squealing coming from the mill?  What type of head is on the machine?

[ScrapMetal]

I've not found a way to get rid of squealing (when it's the endmill) on certain cuts.  My solution so far...



Just sayin'

-Ron

[Thumb]

(03-06-2017, 08:22 PM)Dr Stan Wrote: Are you plunge cutting?  If so make sure you use a center cutting end mill.

Or is the squealing coming from the mill?  What type of head is on the machine?

It is a center cutting end mill and if I do plunge, it doesn't squeal. I don't know what head it is unless you're talking about it being an R8. It is coming from the bit.

[Dr Stan]

Regarding the head I was thinking along the lines of step pulleys V vari-drive.  Worn belts in either case can squeal like a stuck pig.

[Thumb]

OK, it's step pulleys but the belts have less than 5 hours on them. The squeal is definitely from the bit.

[Mayhem]

OK - this is going to sound like a smart arse response but it isn't - have you checked that the spindle isn't running in reverse? Yes - I accidently did this once when I first got my mill, as the switch is the dead opposite to my lathe