Need to Buy or Make (Preferred) Conditioning Rings for Flat Lapping Machine

[Educated Guess]

it's my understanding that the discs for lapping machines are made of a soft sheet metal (aluminium or copper) and have the "diamond grit" pressed int them by means of a steel roller. I've read several lapidary sites describing how to make the discs they use.

Thanks so much. Do you happen to remember the name of the sites on which you saw this info? Would one by Practical Machinist?

Thanks Again.