I believe there must be a mechanical connection between frame and granite. Not just glue or epoxy as for me it will defeat the purpose. Best would be to be clamped somehow to bottom of the frame. But if clamped comes the danger for breaking so a thin layer of polymeric glue will help. Which again makes me doubt the whole purpose.of the operation.

Anyway, for that exact machine polymeric glue will suffice. The kind of glue that fixes metal to metal or metal to stone. It must be sticky like sh_t, not the ones that look like silicone at the hardware store that say xxkg of force, blah blah. I dont know in Uk but in Spain you find that at a place where constructors buy their stuff. Cheaper and much better than epoxy for the purpose.