Microwave Croaked

and

would do

Mine has the drive engage directly with the platter. (I think the term is dog clutch)

But assuming that all the rollers are driven what would cause enough drag to make a platter with roller-drive slip?

Hmm, I guess one of those soup-stirrer scaffold things could, but for most tasks it should be OK.

dent in it

back of the oven:

That'd work until the first big spill. and/or gradually fill up with grime.

possible

Getting the right materials, and budget, could be challenging. a beam that's interrupted by a protrustion on the underside of the platter could work I guess (maybe make the protrusion got most of the way round so it canbe used ad a "foot" for the platter if it's taken out...)

Bye. Jasen