Gary, could it be worth experimenting with some of the metal-fill filaments? I don't know if you've heard of them but they are printed on FDM printers (No expensive laser sintering) but are more expensive. I don't know if any of your machines would be able to use them as I think they need quite a high hotend temperature and a full metal hotend as they are quite abrasive, along side a heated bed.
I found some filaments on amazon quick, never used any metal-fil before however so I can't vouch for any of them.
Copper : https://www.amazon.co.uk/colorFabb-C...opper+filament

Aluminium : https://www.amazon.co.uk/FilaMETAL-A...um+filament+3d

Steel : https://www.amazon.co.uk/AlephObject...steel+filament

I would make them in two halves then just use some threaded rod with two nylock nuts on the end to clamp through a base plate or such, I've done this with a CNC mill with some random plastic we had laying around and it worked really well, but it would be interesting to see what you come up with.