Re: [CAD_CAM_EDM_DRO] Advice on small mill table conversion

----- Original Message -----
From: "Graham Stabler" <eexgs@...>

> I do however need some advice on the motor mounting and leadscrews.
> The screws are 10mm ACME with a lead of 2mm. They run in brass/bronze
> nuts which are quite loose fitting.
> As it stands I am happy with the bed but the screws have far too much
> backlash and the use of washers as bearings is not great either. I
> need to get rid of the backlash and stiffen up the bearing
> arrangement. >
Graham
***************
Hi... as a relative newby here, I suppose this has already been tried, but I
have not seen a thread on this in the few weeks I have lurking.

But--- our company, as one of it's Losing$$ but fun products .... makes
some rifle rests for top level benchrest shooting ... a 0.0001 error (
backlash ) means a 1/2 inch miss at 100 yards ... devastating in a serious
match !!
Anyway, we achieve ZERO backlash in our follower nuts by making them from
Delrin and make them *self-tapping .... the trick is to make them ( the ID )
about 90 % of full diameter of the screw, and make them as long as possible
to take the load as best as Delrin can ...
We have had some of these used about 10 years now, and are still at zero
backlash without replacement ... these are manually wheeled, of course,
and pretty clean conditions, but still, lots of trips back and forth.
This could be worth a try for lightly loaded slides, I suspect I will give
this a try on my current project, rebuilding my xslide on my old SB lathe
.... the real load on the lathes are on the gibs anyway ... might work, will
report if it fails quickly ....

* self tapping ... we usually tap about 3 or 4 threads with a tap to act as
a starting aid ... make the id oversize, if made to the chart, it is very
hard to get it to form the self-thread.

***********
I would like to hear any comments on this " plastic follower nut " useage

.. oh, I might mention that we have a fair amount of falloff from our
lathes; mostly 1 inch, natural ( white) round; if anyone is interested,
we ask 30 cents per inch, plus $3 shipping. falloffs are about 3 to 4
inches in lengths; it makes the neatest self sealing bolts, and slickest
balls etc.
regards, ken campbell, www.deltainc-usa.com





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