[cnczoner]

I was just looking thru an exploded diagram of my mill and you're right -- there is a "thrust bearing" but seems like just a sleeve.

Just spoke with Roton... They claim .006" backlash and .003"/ft accuracy, for the 5/8", 3/4" or 1" sizes. They can also re-load with larger balls for and additional $10 per nut, but that would probably get it down to about .003" backlash. With larger balls, the assembly would "behave differently", but no clear info on how exactly. But if I still need a pre-loaded arrangement to get to zero backlash, I don't see why I'd bother to change the balls.

Zumba -- you said "Get ballscrews for starters. Then get an antibacklash nut.". What exactly are you referring to as the anti-backlash nut here? Is there a special anti-backlash nut for ballscrews? Or were you referring to a pre-loaded double-nut setup?

BTW, Roton and McMaster do not carry pre-loaded nuts, so I'd be interested to hear of some sources for these.

THanks,
-Neil.

[ckm]

I was just looking thru an exploded diagram of my mill and you're right -- there is a "thrust bearing" but seems like just a sleeve.

Adding a thrust bearing will get rid of most of your backlash for about $20 plus a little creative engineering. McMaster has them for about $8 ea in stainless, don't forget a shaft clamp to tighten it up....

Or you can spend $500 on ball screws.

Chris.

[cnczoner]

Adding a thrust bearing will get rid of most of your backlash for about $20 plus a little creative engineering. McMaster has them for about $8 ea in stainless, don't forget a shaft clamp to tighten it up....

Or you can spend $500 on ball screws.

Chris.

Isn't this something I can test for? I expect that if I do my regular backlash test (bring the spindle to zero position from both directions and measure the difference with a dial indicator), then I could measure the play/slop in the thrust bearing with a dial indicator on the end of the leadscrew....right? Because if this really is the main problem, yet it would be a no-brainer to try this first.

THanks,
-Neil.

[ckm]

Isn't this something I can test for? I expect that if I do my regular backlash test (bring the spindle to zero position from both directions and measure the difference with a dial indicator), then I could measure the play/slop in the thrust bearing with a dial indicator on the end of the leadscrew....right? Because if this really is the main problem, yet it would be a no-brainer to try this first.

As far as I know (and that's not much...), you can test for backlash overall, but there is no way to seperate backlash from the nut vs the thrust bearing. You can try tightening down the bearing nut until it's almost unmovable and see if that eliminates most of the backlash, I guess.

All I know is that in my mill, the thrust bearing (or lack there of) was a major source of backlash.

Chris.