was gonna make a ring grinder with the dremel but there's afew issues:
- the cutting wheel shaft isn't perfectly straight so the disc wobbles
- the dremel chuck bit isn't centered so the shaft wobbles
- the original dremel collet chuck might be straighter but have lost it yrs ago. went to b&q and don't sell it.
- the high speed wobbling disc would make the grinding very difficult and inconsistant.
alternative was to buy a ring grinder but it's at least £68! on ebay.
looking at the pic, its just a friggin hand driven grinding disc with some pivot rollers, how hard can it be to make?
so let's make ourselves a ghetto ring grinder
I have here a big diamond cutting disc, pair of metal bushes from a gear selector linkage and the rod from a ratchet clamp which just fits snug in the bush to form the pivot axle.
remove rod from the clamp
blowtorch the rod and bend on a vice to form a crank handle
tap a threaded end
so here's a pair of bushings which will clamp the cutting disc and the washers on either side keeps it centered.
enlarge the cutting disc hole
i could make the housing out of sheet metal but would be alot of hassle, noise, grinding discs.
a block of wood would be easier to do the same job.
so drill a hole parallel to the surface that's the same size as the bushing
cut a slot along the block for the cutting disc
and assembled
no need for a washer on this side cos we'll be pushing the ring against the other side
disc just clears the slot
next was thinking of buying some roller bearings for locating the ring but a simple nail will prob do