I have plastered it over on some other forums.
Lump of flat 3/8" plate.

Chomp it to a disc, chuck it in the press.
Just used a big socket and a piece of tube.

Weld rod onto so I can lathe it.

Take some meat out rebate so the polycarbonate can fit.
I use polycarbonate plastic cause it's got a higher melt point than acrylic.
