[ImanCarrot]

I've designed some jigs that hold optical components while they are being coated. I've had them manufactured from Stainless Steel, but they are very heavy and the machining takes ages.

Is there any other material I could use instead of SS please? Aluminium is out due to the high temperatures involved as is plastic and wood. I'm thinking about some sort of ceramic but am not too up on this at all.

The parts are about 10 inch square plate, 0.25 inch thick and have a big hole about 8" diameter in the centre. The diameter is not whole- there are one or two straight sections off it (cutting down the volume of the circle. The circle thickness (0.25") is angled at 60 degrees and the straight edge at 45 degrees.

There are about 8 smaller 4mm dia holes round the big circle and four M5 screw holes at each corner of the square.

The whole thing operates at about 300 degrees celcius and very high vacuum so it needs to be about the same thermal expansion co-efficient as glass although I've designed some "give" for this.

Any ideas appreciated- I have searched for days for a suitable material to no avail... can you machine ceramic like this? can you put a threaded M5 hole in ceramic?

Thanks in advance.

PS- it needs 4 locating pins too which at the moment I get push fitted and spot wleded in place. It looks like this: