The 5th axis preload setting that keeps tripping up new guys

I run a Haas UMC750 at a shop outside Phoenix and every few months we get a fresh operator who messes up the same thing. They bump the 5th axis rotary preload up too high because they think tighter is better. I caught a guy cranking it to 80% last Tuesday on a titanium job and had to stop him before he trashed the trunnion bearings. Haas says 30-40% is the sweet spot for most jobs I've run. Why do people always assume more clamping force means more accuracy?

2 comments

2 Comments

sage_lewis103d ago

80% on a titanium job?" That's wild, man. I've seen guys crank it up like that thinking they're gonna get tighter tolerances but they just end up eating bearings for lunch. 30-40% has always been the rule here too, anything past that and you're just asking for a rebuild.

the_luna3d ago

Exactly. Chasing extra tenths and blowing up a $4000 chuck just doesn't make sense.