Re: [CAD_CAM_EDM_DRO] nut backlash comp. was re:Re: Ball screws for CNC plasma cutters

Hi Ballendo,

The method you describe is an alternative, simpler method to the one I have
used. I have used your method before but, as you recognise, wear soon
becomes a problem. The method I am now using, with two separate nuts,
doesn't seem to suffere as badly. Pinching the nut together at right angles
to the leadscrew perhaps wears more significantly as it is just deepening
the thread over part of its diameter whereas using two nuts adjusts the fit
to full depth on the opposing flanks of two threads. That is, the load of
the screw is spread over a much larger area of metal in the second method
than the first.
The problem with the spring loading method is that it introduces drag which
has to be overcome with the drive motor and increases wear. On a large
machine this is not too much of a problem but, on smaller machines this can
be significant as friction is far more of a problem.

Ian
--
Ian W. Wright
Sheffield UK
www.iw63.freeserve.co.uk

----- Original Message -----
From: <ballendo@...>

> This is similar to the anti-backlash nuts used in the import
> mill/drills. They use a long nut, with a slit near one end (making
> two separate "thread bearing" areas). The slit does not go all the
> way through, so there is no alignment problem. Anyway, there is a
> backlash adjustment screw on one side of the 'main' leadscrew which
> is positioned to "squeeze" the slit closed. Like your approach, this
> will eliminate backlash. For awhile. THEN,...
>