Re: Bridgeport ballscrew backlash

Hi I can only comment on the UK on my Boss 3 the ball nuts are not
adjustable. They are preload by selecting the correct ball size and
number. This makes it very difficult to do as you need to have many
different sizes of balls. The seals at the end of the nuts
(Thomson?) are also difficult to source. I had my x axis (10 thou
backlash) profesionally rebuilt for £250 (ca $500) with a local
company called jena-tec. They also have a USA base (Jena-Tec Inc,
333A Bell Park Driv, Woodstock, GA 30188, U.S.A.
sales@... www.jena-tec.com). They measure the backlash,
clean and buff the ball screw and refit using new balls and
appropriate preload. I can no longer measure any backlash on the X
axis when installed. On the x axis of a Boss the thrust bearings
acty on the ball nut (it rotates) whilst the actual screw remains
fixed. The Y axis is more complicated as according to the BP manual
you need to have the ball nut holder matched to the ball nut and
screw. Others might like to comment of if this is really needed. I
bought the mill cheap and retro-fitted (it was already partially
done with an Ahha card) thus the cost of removing the backlash was
not to much of a problem and I now have a much better mill.
Fred


--- In CAD_CAM_EDM_DRO@yahoogroups.com, "rocketscientistnate"
<rocketscientistnate@y...> wrote:

>
> I have a Bridgeport (was a Boss 5) that y'all helped me rebuild

with

> gecko drivers last fall. Thanks for all your help, its running
> great even making a little money. I has about .002 backlash in

the

> ballscrews, both X and Y, and I was wondering if anybody know a

good

> place to have them rebuilt, or to buy replacements. It's not a
> major issue, since my software (DeskCNC, which is a great program

by

> the way) compensates for it. But I have broken a few cutters when
> the direction changes suddenly in a program. I've been told there
> could be a way to adjust them, but nobody I know seems to know how.
>
> Thanks in advance
> Nate