Re: [CAD_CAM_EDM_DRO] Re: Backlash

Vince Endter wrote:

> I have a second mill with ballscrews about the same size of the Hiwin,
> and simular precision match pairs of radial contact bearings. The
> backlash on that machine is .0002" on the Z, .0006" on the y,
> and .0008" on the X, and this machine is 20 years old. That is why I
> don't understand how I am getting .004" on the Hiwin ballscrews. I
> have taken the same measurments on both machines with the same
> indicators in the same way.

I think your table is bound up in some way. You say you
loosened the gibs and it STILL took maybe 100 Lbs to move the
table? That is incredibly wrong, and you need to find out what
is going on in there before the entire hand scraping job is
totally wasted! I don't know whether there are big chips in the
oil grooves, abrasive somehow left in the ways, the scraping
somehow wasn't done right, or what, but there is NO WAY it
should need that kind of force to move it. In fact, a dry
way shouldn't take that much force to slide, like when I'm
spotting the ways during scraping. Maybe 20 Lbs to make it
slide, with a hint of spotting dye on the contact spots.
With proper way oil in there, it should float like a boat on a lake.

Jon