Ball-Bar measuring technique and mapping ballscrew

[AKFALAR]

I have been working on building a Ballscrew waterjet table.

I was thinking about using Roton screws w/ double nuts. They say its .003" / ft error tolerance.

What is a ball-bar or is there another technique to map the screws errors for more manageble precision in this setup.

I saw some reference to using a ball bar to verify accuracy.

Thanks.

AKFALAR

[ConKbot of Doom]

I believe ballbars are just for checking everything overall afterwards, Ie, making sure everything is working smoothly together, not just measuring the ball screws. Laser interferometers can be used for mapping ballscrews, though getting it done could be a bit pricey.

[BobWarfield]

Yep, ballbar not for mapping, though useful for other checks.

To map you need a reliable standard. It can be done by creeping gage blocks along 1" at a time, though that is painful. You can hire someone to bring their laser interferometer as has been mentioned. Or you can use a suitably accurate DRO scale.

Best,

BW