Re: [CAD_CAM_EDM_DRO] machining ballscrews

I had a long talk with Don Fergle at NAMES about ballscrews. Don was a
ballscrew design guru for many years. He is now just a wonderful
semi-retired fellow with lots of knowledge to share.

Les, I recall our discussion about the major diameter of rolled ballscrews
not necessarily being concentric with the running surfaces. Don passed on a
good trick for holding the screw in a three jaw chuck for turning.

Find a coil spring of a diameter and wire gage such that it will thread over
the screw. Now tighten the chuck on the spring. The spring wire is of
consistant diameter and will hold the root of the screw thread concentric
with the chuck.

Of course you need to find a spring without flattened ends or grind those
ends off. Mr Fergle says it works very well.

Doug

----- Original Message -----
From: Les Watts <leswatts@...>

> I machine them in a lathe in the hard state with carbide. I then use a
tool post grinder to bring them to size. The core is about RC40.. soft
enough to do the threads with a single point tool. Lately I have been
saving a lot of time by knocking off most of the hard case before turning
with a Milwaukee hand angle grinder. I just grind until I don't see the
lands any more.
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA
> http://www.rabun.net/~leswatts/wattsfurniturewp.html