Re: [CAD_CAM_EDM_DRO] Best source for inexpensive ballscrews?

On Sat, 1 Aug 2003, Kim Lux wrote:

> A 5/8" ballscrew is pretty weak because the balls make the core of the
> screw fairly small. We used one in the cross slide in our lathe and it
> is good for that, but not much more. Furthermore, if you are using
> powerful servos you can overload them pretty easy.

The mill I'm working on weighs a total of less than 100lbs. I think the
5/8" will be sufficient.

> One other thing: consider getting the high accuracy ballscrew for at
> least the X axis on a mill. They aren't much more money and if you
> machine larger parts they are almost a necessity. Consider this: on an
> 18" piece with a standard precision ballscrew the error could be 6 thou,
> which is considerable in my books.

Yeah, your talking big machines.

> One more thing: McMaster Carr doesn't cut the ballscrews if you order by
> the inch. They order them from Nook and it will take several weeks to
> get one.

The 5/8" wasn't special ordered, but the bigger sizes may be. I think
it's common enough that they keep it in stock.

> The next thing you need to concern yourself with is attaching the
> bearings and drive system to the ballscrews. They are hard (Rockwell
> 45C ?). We machined ballscrew spindles and pressed them on.

I annealed the end of mine. I tried machining before hardening, but that
was a bit too much for my 7x12 lathe.

C|