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Darren's active projects

Darren

Ultra Member
Premium Member
I couldn't help the laugh icon.... My friend Fred got ultra-precision ballscrews on his 10X50 mill, and he doe curse them from time to time. He had slowed down using it these days, so it is more frequent that he forgets to lock Y.... He and I laugh when it happens!


Nice that you managed the save! That is one powerful machine!

Its only happened twice to me when it has mattered and both times I was able to save the part. On things like facemilling, I don't lock it and it never moves enough to matter.

The first few roughing slots on these parts were done at 0.950" depth and the Y didn't move at all. Got a bit hot so i stepped back to one 0.500 and a 0.450 before I switched to a finishing mill.
 

Dan Dubeau

Ultra Member
I have always heard that repeated, but this I think is the first instance I have seen of proof that this actually happened to anybody. Glad you were able to save the part.
 

Darren

Ultra Member
Premium Member
Yea, thats why I figured I'd post up. Its does happen, but its not like it takes off like some people seem to think. It takes a heavy cut. That said, I will take ballscrews any day over regular screws. Zero backlash is very nice.
 

PeterT

Ultra Member
Premium Member
@Darren you obviously have used both ball screws & regular screws on mills. The other thing I've heard about ball screws is the act of locking can displace the table because they are free-er to move (DRO reads 0.000, lock the axis now DRO reads 0.002"). This seems counterintuitive. Now I think this was coming from a guy who CNC retrofitted an RF-45 or similar mill & those stock dovetail locks are not the best from my own experience, they torque on the gib strip which can add a displacement component.
 

Darren

Ultra Member
Premium Member
Peter, my locks don't usually move the table much at all. Maybe a few tenths if anything. I think its probably due to the preload in the ballscrew nuts and bearings. Once in a while the dro will creep off zero on the locked axis while milling after the axis is locked, but its really nothing. I'm not pretending to be Robin Renzetti here.
 
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