Re: [CAD_CAM_EDM_DRO] Re: Steel plate for hexapod bed

Simon Arthur wrote:

>I thought about granite, but how do you attach fixtures?
>
>

You drill holes with abrasive slurry on a piece of pipe (core drill)
or a real diamond core drill. Then, you bolt on the fixtures, and maybe
even apply glue before tightening the bolts. That's how Excellon makes
their $100,000 printed circuit board drills. The use a HUGE granite
slab, and glue and bolt a granite beam to it as the X axis slideway. A
"cross"
fits over that, and carries another granite beam as the Y axis. The table
slides over the Y beam on air bearings, resting on the big table.
It is insanely expensive, but makes an incredibly reliable precision
X-Y table for light drilling. The gantry over the table that holds the
multiple drilling spindles is also granite, and the drill motors use air
bearings. (I have some of the pieces off one of these machines,
and some of that is now the X-Y drive for my CNC Bridgeport retrofit.)

Jon