Lathe Ballscrews

[mick41zxr]

Hi Not an Acorn question directly.
However, I am planning a lathe conversion & was wondering the importance of removing backlash in a lathe.
The reason being is in a lathe all cuts are made with the lash being taken up in the cut
(being adjusted for in backlash comp) as opposed to a mill.
Are single nut ballscrews acceptable?

Thanks,
Michael

[Dave_C]

Hi Not an Acorn question directly.
However, I am planning a lathe conversion & was wondering the importance of removing backlash in a lathe.
The reason being is in a lathe all cuts are made with the lash being taken up in the cut
(being adjusted for in backlash comp) as opposed to a mill.
Are single nut ballscrews acceptable?

This seems like a yes or no question but in reality it is not as there are very loose single nut ball screws and there are zero backlash ball nuts for ball screws that work quite well.

However, I'd have a different opinion regarding 'All" cuts being made toward the headstock as I make some cuts from time to time that are toward a shoulder opposite the headstock.

But yes, a single zero backlash nut can work quite well. And if your find you still have some backlash, you can account for it in Acorn.

Dave C.

[mick41zxr]

Thanks Dave,
In milling terminology I cannot think of a situation where you would go from a conventional cut to a climb cut in a lathe. All cuts are conventional, even when cutting towards the tail stock. It has become second nature when working on a manual lathe to back out an extra half turn before feeding in to take a cut.
I have limited space for the cross slide screw, so probably need to go to a single nut 12mm ballscrew. Trying to work out if there are any negatives for this. I'm thinking lash adjustment should address most cuts.
Regards,
Michael

[martyscncgarage]

Might be too large, but check out these guy's 1605 ballscrew and nut offering:
https://www.homeshopcnc.com/Ballscrews/ ... 76156.aspx

[DocsMachine]

What? There's lots of cases where the tool changes direction, and a small amount of slop can become apparent.

Turning a sphere, for example- the tool starts at the "top" of the ball, and starts cutting in the X+ direction. It makes it to the widest part of the ball and reverses to start back toward the X- direction. Slop would show up as an inaccuracy at the equator of the ball.

Ditto making a hollow, whether straight sided or curved. Or a "ring" feature, like the collar below the ball at the top of the "Pawn" test part.

I have a conversion lathe that uses no-name eBay ballscrews, with single nuts- I didn't know about "anti backlash" nuts when I made it. But, although it still has fairly low hours on it, it's proven quite accurate for my purposes.

Doc.