Re: RE: Z axis conversion

"SMITH, THOMAS B. (JSC-DX)" wrote:

> From: "SMITH, THOMAS B. (JSC-DX)" <thomas.b.smith1@...>
>
> I can't help you with the z axis conversion, but that reminds me that
> I
> wanted to warn people about the z axis on Asian mill/drills. Once I
> installed my DRO, I decided to check it's accuracy. I compared all
> three
> axes to the DRO, and the Z axis was OFF by about .020" per inch!! One
>
> revolution of the dial was .098", not .100") The X and Y were
> perfect.
>
> I thought it must have been something wrong with the encoder, or
> something
> else in my DRO installation, but using, a dial indicator confirmed
> that the
> graduated collar is way off. The problem must be in the gear ratio.
> This
> was on a Grizzly model 1007(?). Has anyone else noticed this, or come
> up
> with a fix?

WOW! The gear ratio is usually 2:1, which is not too hard to get. The
handle
goes one full circle for .100", and the lead screw is generally the same
as the
X and Y screws, at .200" / rev. It shouldn't be too hard to check the
gears.
One way is to pull the Y bearing bracket off the front, and unwind the Y
screw
from the yoke. This gives pretty good vision and access to the inside
of the
knee. Either way, you could have them replace it, as it is an accuracy
problem. Since you have the DRO, you might not worry about it any more.

But, if anyone else has this sort of error on a new machine, they should
get
a new part at no cost!

Jon