Tried climb milling 4140 on my old Haas to chase a nicer finish, and it bit me

I ran a batch of 40 shafts out of 4140 pre-hard last month and decided to climb mill the whole profile instead of conventional like I always do. Every machinist I know swears climb milling gives you a better finish, and yeah, the side walls looked great, but my inserts were shot after 6 parts instead of the 25 or so I normally get. Turns out my old machine has about 0.003 inches of backlash in X, so climb milling let the cutter get dragged into the cut instead of pushing away from it. I switched back to conventional for the roughing pass and only climbed on the finish pass, and insert life bounced right back. Has anyone else had backlash eat their tooling on climb cuts, or is my mill just due for a screw replacement?

1 comments

Log in to join the discussion

Log In

1 Comment

ericp6721d ago

Had a similar fight with the X screw on my old Bridgeport clone years back. Kept blaming the inserts until I put a dial indicator on the table and watched it jump when I reversed direction. A new nut took care of it and my climb cuts quit chewing up carbide.

0