I have a recurring need to reach inside a closed space and grind a weld. Sometimes I have enough room to get a right angle die grinder in there, if I distort the shape, but then I have to distort the shape back, which is kind of a pain. Sometimes there is not enough space to do that, depending on the size. I use a 2 inch Roloc disk on the die grinder as a kind of miniature right angle grinder. The headroom requirement for that setup is 4 inches, more than I would like.
I was thinking that I might make a stationary tool, basically offsetting the Roloc disk a few inches via a drive belt or chain, to reduce the headroom required to get inside and grind the weld. The Roloc disk mounts on a 1/4 inch shaft, so perhaps I could put two bearings and a pulley on that 1/4 inch shaft, and then run a drive belt to the die grinder, which would have another pulley on it, using a 1/4 inch shaft mounted in the die grinder. The sketch at the link below should help, I always have trouble visualizing what people describe in words, a picture is worth a thousand words, etc.
Maybe there is another solution that I have not considered.
Richard