Hi!
If you look at the restored disc in the topic close to this you can see how my restore looks. It was made with a machine ( I dont know the name in english but translated direct from swedish it might be a rotating magnetoboard with radial working grindstone) to witch I built a extra disc where I can mount the hondadisc to grind the frontside. Backside is easily done as the disc is ”glued” on the magnetoboard. You need to find a machineryshop with that kind of grinder. Unfortunately the company not far from me went bankrobbed so now I do not know where to do it anymore.
Kind regards, Bo from Sweden.