Re: Ballscrew question

Paul,
I have an X2 mini mill I converted with McMaster Carr 5/8" ball
screws and single nuts. I see .002" on one axis and .003" on the
other two. On the axis with .002, I unloaded all the balls from the
ball nut and re-loaded it with .001" DIA larger balls. The nuts are
supplied with .124" balls and McMaster sells .125" +/-.0001 hardened
chrome steel balls (9528K11 100pcs. $2.50). With the .200 pitch of
the ball screw it does not take much rotation to compensate for the
backlash. The screws have not had much wear-in time yet so these
numbers may open up a bit. My feeling is, they are a vast improvement
over the soft steel screw / bronze nut / .006-.012 backlash as
provided with the machine.
If you make the mount for the ball nut threaded straight thru, with
two setscrews for locking, you can put a nut in each end and adjust
the pre-load mechanically. This way you get a double nut for the
price of two singles. I have seen this done on $8000+ turn key
machines with good results.
My $.02
Ken
--- In CAD_CAM_EDM_DRO@yahoogroups.com, "yodawill2000" <chue2k@a...>
wrote:

> Im about to convert My RF31 clone to ballscrews as the backlash
> will be intolarable after the cnc hardware is installed ..
> Heres my question for the Guru's ..
> Do the singlenut ballscrews have noticable backlash ??
> Or is the more costly doublenut screws the only way to go ...
>
> I realize the doublenuts are superior but Im curious if the
> singlenuts will be good enough ..
>
> Thanx in Advance for any help here ..
>
> Paul In Texas ..