Re: [CAD_CAM_EDM_DRO] Best ball screw prices? (was: Ball screw load ratings)

Doug Harrison wrote:

> ----- Original Message -----
> From: Jon Elson <jmelson@...>
>
> > > Does anyone have a source whose price is significantly (5%+) less
> > > than Thomson's? All I found so far is Reid Tool, and they're a few
> > > cents cheaper.
> >
> > Supposedly, HiWin has the best prices, or at least, very competitive.
>
> I got quotes on Hiwin for ballscrews and linear rails. The rails were half
> the price of Thomson. The ballscrews were cheaper than Thomson from Motion
> Industries but still significantly higher than Thomson from McMaster-Carr.
> For some reason, they are dirt cheap from McMaster-Carr if you stay with
> 5/8, 3/4 or 1 inch sizes.

All of this is probably rolled thread low-precision screws for power transfer,
not for CNC positioning. The nuts are probably single-track, with no
preload. And, the manufacturer probably does not recommend preloaded
nuts on these screws. I've used some of this stuff (Thompson) in a proof of concept
machine, and while they work, they are VERY loose. I later had to replace
the screw with a BSA screw with plastic anti-backlash nut. That was for
an optical carriage, so there was no force to speak of. But, these ballscrews
would not work very well for a high-quality CNC machine.

Jon