Re: Ballscrew Nut-blocks and Thrust bearings

Hi Leslie,

Could you please email me the AutoCad drawing of your end bearings.

I have to convert to ball screws and I am evaluating my options.

My mill now has 32 mm (1.25") lead screws for the 10 x 54" table. Do you think 1" ball screw can handle the load?

Bertho Boman
===========================================
Leslie Watts wrote:

> From: Leslie Watts <leswatts@...>
>
> I designed and built ballscrew end bearings similar to the Thomson units
> to save the $2400 or so to just buy them. They use two 40 degree angular
> contact bearings in the DB preload configuration. The cost for steel,
> bearings and seals was about $40 per unit. I have a poorly drawn autocad
> design file for 17 mm bore units that I would be willing to e-mail to
> anyone who needs it. Much machining work to .0002" tolerances is
> required.
>
> I ended up with Hiwin ballscrews. The 25 mm units are sold as a single
> 2.5 meter length with two oversize ball 5% preloaded nuts. List price
> for these are $320 for the .002"/ft lead accuracy C7 grade. Normally
> these are cut to make two 1.25 meter units each with one preloaded
> flanged nut.They look ok but end machining service is not available so I
> spent the weekend at the lathe. The RC 55-60 casehardened screws can be
> machined without annealing with carbide tooling. The core is about
> RC 40.
>
> I was told by a Saganaw engineer to not flatten the wave washer also.
> But for my large machine the preload is just not enough hence the
> oversize ball method.
>
> Leslie M. Watts
> ITW Advanced Technology Group
> (847)657-4559
> http://www.netcom.com/~leswatts/leswp.html