ATM Cutting aluminium rings.

["Marco Miglionico" <marco.pm@btopenworld.com>]

Hello all.

I'm working on a design for a new scope. (12.5in Dob). For the secondary
cage
I am going to use the standard  2-ring cage. However, instead of
9mm ply for the rings, I want to use sandwich construction with aluminium
faces (0.7mm) and poly(somethingniceandlight) core all bonded together.
The problem I am going to have though is how do I cut a 16in OD 14in ID
ring(s) from 0.7mm thick sheet aluminium?

The only thing I can think of,  is to jig-saw it out between thin layers of
wood
while turning the piece on a bolt, which isn't ideal because the blade never
seems to want to stay vertical and perpendicular to the surface.

Any better ideas?

Thanks.

Marco Miglionico.