His Divine Shadow posted:

I dunno if this is the right place to ask this, but I am building a small belt grinder that will use 2x36" sanding belts. I intend to use it to sharpen chisels, plane irons and knives. It'll be a home built contraption like a wooden harbor freight lookalike. My question is where do I want to go slow and where do I want to go fast?

It seems like those that have bigger grinders like 2x72", prefer really fast speeds like 6000 SFM, I assume it's because it hogs of more metal faster and zirconium belts work better at higher speeds unlike AO ones. On the other side there's machines like the sorby pro edge which has a very slow speed like 700 sfm. What gives, why are so many people saying go for speed, but one of the pro sharpening tools on the market goes slow?

Is that just because it's for sharpening and doesn't need to remove as much material as other metal shaping operations, or is there more to it? Perhaps finer grit belts work better on slower speeds?

At any rate I am building this with step pulleys so I can have a range of speeds. I think 890rpm to 3500rpm is a suitable range.