Quote Originally Posted by Jonathan View Post
Can you think of anything better to use that's not too expensive? Maybe plywood, but I guess that's not much better. Vacuum table isn't much good for metals. Bear in mind it needs to be about 800x1900mm ... so clearly I can't afford a nice piece of tooling plate that size!

I'm not sure about the epoxy idea either, wouldn't it just crack/crush?
Jonathan any type of wood table is going to fail to sufficiently clamp metal to it

Whatever you are machining/clamping to the table has to be weaker than or equal strength to the table itself. So the minimum would be ali but it would be cheaper to use steel.

A steel plate with 50x15 bars with 70x15 bars mounted on top to form the tee slots your require, and steel would be my preferred material.

Steel wont warp when wet/different humidity you would have to set your X & Y Axis to run parallel to the plate, now you might think this is a disadvantage not being able to machine the bed to suit the X & Y

But you can only get a flat surface this way if the material is thin as a very thick piece will show any misalignment.

Phil