Re: Ballscrew bearings

stratton@... wrote:

> From: stratton@...
>
> I know in an ideal world I'd have the space to mount (and the cash to
> pay for) a pair of the premanufactured ballscrew end blocks. But I
> don't, so I'm trying to come up with a smaller, simpler, cheaper
> alternative that will still give acceptable performance on a lathe
> crosslide, which doesn't need to move very fast.
>
> Any suggestions?
>
> (Fortunately all this mounts in brackets I'm making from scratch, and
> the screw itself is cheap, so I can always redo it later if I'm
> unhappy with the result.)
>
> Chris
>

Cris, you may have seen my postings in the past about shop - made
ballscrew end bearings using DB angular contact ball bearings.
These of course are too big for a lathe retrofit.

On my Boxford lathe the cross slide and compound screws are fixed
at on end with deep groove ball thrust bearing pairs. preloading is
set by shimming or grinding the back of the washer portion of
the bearing. These are much thinner than tapered roller or angular
contact and thus are easier to deal with. They can take a light
radial load as well.

I really think one end free would be fine for a lathe cross slide; you
don't have critical speed or buckling load problems unless the
screw has a tiny diameter. Seems to me 1/2" or larger screws
would be fine in the fixed-free configuration. Was there another
reason you were considering fixed-fixed mounting?

--
Leslie M.Watts
Illinois Tool Works
Corporate Advanced Technology group
(847) 657-4559
http://www.netcom.com/~leswatts/leswp.html