Re: Surface plates as a base for tooling

As Jon mentioned, some of the extraudinailary high priced PCB
machines use granite for the base.

For a home mini (router/pcb/etc) the granite offers some benefits
that aluminum and steel don't.

One is that it is FLAT, so that makes it easier to start with.

Then it is solid so as you assemble, there are no sections that don't
fit just right.

Then there is the mass of the unit to keep it from moving.

If you have the $$, Starrett will drill whatever holes you want on a
special order plate. If you have a concrete drill you can drill your
own.

For mounting the rails, I would mount one side by drilling the holes,
and using a epoxy secured bolt. Then using one side as the
reference, secure the other side.

Another benefit is that with the cheap import stuff, a Granite
surface plate will not cost too much. A 12x18 from Enco is about 30
bux.

Dave




--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Ray Brandes" <RBRANDES@G...>
wrote:

> Dave,
> I wouldn't know how to attach machine components to granite. I am

sure

> it can be done though. Aside from the stability offered by the

weight,

> I don't see any advantage over aluminum jig plate.
> Regards, Ray
> If your post isn't off topic, I don't think my reply should be

either!

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "turbulatordude"
> <davemucha@j...> wrote:
> > Hi All,
> >
> > I checked my T-Tech PCB mill and found it was based on a 1/2

aluminum

> > plate, ground flat, and then added the linear rails.