Anybody made up anything from scratch for this purpose?

Seems to me the characteristics of grinder grit are considerably different than woodworking dust (heavier for one thing) so I wonder how well the woodworking collectors work for this purpose.

-Unfortunately, in their normal configuration, they don't work. The dust cakes up on the impeller until it gets seriously out of balance and finally throws off a big chunk, at least that's what happened when I tried it... Lots of serious sounding noises that can't be good for the blower. Now if you can arrange to have the blower sucking on a filter box that collects all the dust and grit it'll probably work pretty well, those puppies suck air like a pack of Hoovers on steroids.

- They won't work. The grinding dust will cake on the inside of the collector tube.

Build a 'backstop' box to catch the dust, or mount the grinder on a 55 gallon drum.