Re: [CAD_CAM_EDM_DRO] Re: Ballscrew balls ?

>
> On Fri, 7 Apr 2006, ballendo wrote:
>
> > But you CAN improve things greatly by using oversize balls and running
> > them in, and then re-loading with fresh--oversize--balls. It's a very
> > good way to maximise the effectiveness of your inexpensively purchased
> > components...
> >
>
> what size do you use? i haven't gone through all the iterations of sizing,
> but it seems that off-the-shelf at the major catalogs will have only
> 1/8"dia. (0.1250") with the next size up being 3.5mm (0.1379").
>

as a follow-up to this topic, i tried 0.1260" dia. grade 25 chrome balls
today in the 5/8"x.200 standar ballnuts and rolled ballscrews and here's
what i noticed:

-after getting 15-20 balls in there, there was binding. (and probably no
backlash :)
-also tried alternating and randomizing 0.126" and 0.125" balls and while
i could get more balls inserted and the resulting binding was
less, it was still present (no free-spinning)
-also "tried running them in" (assuming you mean to induce this binding
and then run the ballscrew back and forth until the binding disappeared)
only on a short piece of ballscrew about 6" in length

it seems that either i can put as many ofthe 0.126" to fit and then crank
the screw back and forth until binding disappears for a "custom" fit or
use 0.1255" dia balls (don't know how much of a difference this will make)
or stick with reballing with 0.125" and live with the near-zero backlash
(i'd like to say 0.001" but was probably getting 0.002"-.003")

has anyone else tried reballing?

thanks!
david


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