On Fri, 14 Nov 2008 18:51:29 -0700, "Bob La Londe"
wrote:

"Pete C." wrote in message
nster.com...

Bob La Londe wrote:

"Pete C." wrote in message
ster.com...

Bob La Londe wrote:

I have been playing with my new little Taig CNC setup. Getting it
snip
Right now I am in the process of
designing and building some clamping fixtures for engraving sheet to try and
take out some of the variance by flattening it in the clamping fixture. So
far the best thing I have come up with is a square made out of angle with
t-bolt screw down tabs on the outside of the square and a floating clamp
plate on the floating side of the square. I figure I'll make two or three
so I can at least clamp flat the section I am working on. Maybe a 5 x 5, 5
x 8 and 5 x 12. This would allow me to make engraved plates up to 10 by 12
with my 5.5 by 12.5 working area. I think I'll have to go with something a
little different though for the mold making I plan to do after my engraving
project is completed. I don't think that will be as big a deal though since
I'll be starting with much thicker stock. Just surface it, re-zero, punch
my index holes, and then run my code.

I've got the pieces of the 5 x 5 partially clamped up and ready to be
welded, but I think I'll wait until tommorrow amd all the details have
worked out in my head before finalling that one. I am using some scrap from
another welding project to make these clamps and I do not want to waste any
material.

Big CNC routers use vacuum to hold sheet material flat. Could you rig
something like that? Maybe google on vacuum chuck.

Pete Keillor