Machining Ball Screws Accurately

[Michael GilliganParticipant @michaelgilligan61133]

Posted by blowlamp on 18/11/2020 16:19:41:

Can anyone say why it needs to be more complicated than I have already suggested?

When I machined some ballscrews a while ago, I think I found a suitable spring and wound it along the thread – a bit like a Helicoil. As the spring sat higher than the peak of the ballscrew I was able to grip the spring in the jaws of a good three-jaw chuck and so machine the screw.

Martin.

.

That does seem a reasonable approach, Martin

… although, of course, we don’t know if your results matched Joe’s ambitions

Mine was simply an observation prompted by the direction in which suggestions were evolving.

MichaelG.

[blowlampParticipant @blowlamp]

Posted by Michael Gilligan on 18/11/2020 17:57:22:

Posted by blowlamp on 18/11/2020 16:19:41:

Can anyone say why it needs to be more complicated than I have already suggested?

When I machined some ballscrews a while ago, I think I found a suitable spring and wound it along the thread – a bit like a Helicoil. As the spring sat higher than the peak of the ballscrew I was able to grip the spring in the jaws of a good three-jaw chuck and so machine the screw.

Martin.

.

That does seem a reasonable approach, Martin

… although, of course, we don’t know if your results matched Joe’s ambitions

Mine was simply an observation prompted by the direction in which suggestions were evolving.

MichaelG.

Hi Michael, thanks for replying.

I'm only wondering how much better it would be possible to achieve.

The wire sits at the bottom of the thread (ball track if you like) and because the wire is of uniform diameter it makes an even offset from the bottom of the thread. Once it's gripped in a collet or good chuck then I think the method stands every chance of holding the part concentric to the thread itself.

All that said, I'm sure a ballscrew can simply be held by its outer diameter and machined as required without worry as long as the chuck or collet is good. All the ballscrews I have had to machine have needed straightening before machining and that can be a faff in itself.

Martin.

[John HaineParticipant @johnhaine32865]

I've used Martin's method for ordinary screws to machine a concentric spigot on the end and it works well. I wound the spring from soft steel wire.

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