The cam retainer plate started life as a piece of 8mm thick 7075-T6 aluminum plate, so the first thing to do was to turn it into a 0.125″ thick piece.
Hodgson Part 009/110, Cam Pad Support and Retainer Pad
To save myself a little work, I used some stainless steel 6-32 hex threaded circuit board stand-offs to make the Cam Pad Supports. The spacers I bought were 18-8 SS, Male-Female, 1/4″ Hex, 6-32 Screw Size from McMaster-Carr, P/N 91075A444.
Hodgson Part 012, Cam Retainer Plate Spacers
I had some scrap 7075-T6 aluminum left over from some other parts so I knocked off the corners until I could fit it into a collet. I then rough turned it down until is was round.