Re: [CAD_CAM_EDM_DRO] Re: real granite machines!

Jon Elson wrote:

> I think a granite slab would make a great slide for a machine. Bolting and
> gluing several slabs together would be a lot easier than making monolithic
> complex shapes.

Granite has compressive strengths of about 19 Ksi whereas it is easy to cast the desired shapes in concrete you will loose some
strength.
Using some of the newer techniques it is possible to get concrete with compressive strengths in the 12 Ksi range. Embedding steel
in this and providing decent anchors should not be too difficult.
Likewise one could drill holes in granite and mount components using a filled epoxy to set anchors and maybe come out OK.
The local tombstone company would seem to be a better source than the lab grade stuff. I have seen 4' x 4' by 1' pieces for a
couple thou. (Boeing).
I find the idea of a small masonry based gantry intriguing but hate to think of the energy necessary to accelerate the mass
involved.

My thinking goes more along the line of an L shape with cast iron ways, etc anchored in masses of concrete. Has anyone tried this?

Dave