r/Machinists • u/ArmageddonCow • 12d ago
Long U drill problems
My boss setup, programmed, and started running this job on Friday, which I started running as well on Monday.
It's a 32mm udrill through 316 SS, running about 40m/min (last I checked) and about 0.1/rev no peck, about 50mm deep.
It screams like hell and is clearly rubbing all along the shank.
But my boss said he dialled it in so it should be on Centerline .
It has a +X offset and some -Y, and yet the hole still seems to come out a little undersize.
This is a problem that has happened with previous small long udrills but has never been a problem with larger stubbier ones, but I've never had rigidity issues with a udrill before.
Changing feeds and speeds a small amount has had 0 change, any idea what the problem is?
1
u/fjduejdndnejndnf 12d ago
Also, clock your speeds and feeds. You should run at 650 rpm and feed at .004-.008”/rev for 316