Re: rolled ball screws

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Les Watts" <leswatts@a...>
wrote:

> I use the oversize ball preload rolled screws on my gantry.

Specifically

> it is the HIWIN 25mmx5tpi.
>
>
> It is my understanding from talking to the HIWIN engineers that

oversize

> ball
> preload is very stiff but is four point ball contact. As such the

balls are

> prone to
> scuffing and somewhat faster wear. I still expect at least hundreds

of

> kilometers
> lifetime though. For industrial that might be a couple or few

years. For

> hobby
> stuff it is forever if they are kept very clean.
>
> I did notice a 50% reduction in preload drag torque after about a

10 hr run

> in...
> but I cannot say it is the ballnuts. I suspect it is just the

transmission

> and end bearings
> seating as I know they create most of the drag torque from my

measurements.

> There are 16 5% preloaded bearings in my x axis alone!
>
> Les
>
> Leslie Watts
> L M Watts Furniture
> Tiger, Georgia USA

Hi, where where you getting the oversized balls from?
did you have a asortment of balls available for testing
what size did you end up using?
Did you replace all the balls per nut?

I like to do this so thanks in advance for anybody that can
contribute some info here.