I totally agree with Stacy about this.
When you're running a grinder at the speeds I do, it's truly frightening to think what could happen if there was a catastrophic bearing failure or contact-rubber failure, etc. The thing could go off like a bomb, plus the edge of those belts might as well be band-saw blades. They'll zip through your tendons with great ease. If any part of you in along side that belt when a bearing goes and that belt suddenly comes off, you're probably going to the hospital with severe injuries.
I've built several high-speed belt grinders. I'll build it all but the motor and the wheels/bearings. These I get from Bader, usually off-the-shelf, or sometimes made to order. There's not much to a belt grinder, really. I think the precision of the wheels/bearings [particularly the contact wheel and tracking-idler pulley] is what makes the difference between a quirky machine and a rock-solid, glass-smooth, quiet-running machine from the moment you first spark it up.
I've been hurt too many times (which means pain and usually weeks of no productivity) with stupid technique or stupid machines (or both) to even think of chincing on a machine that could mame me beyond recongition so quickly.
If you're running it slow, it might not be too bad, but why even build a grinder you can't turn up and really use?