You can cut any thickness at all....if you have the time.

I've done 3/16" with no problems.

I use all sorts of bits for mine - just drilled a lot of holes in seashells for my daughter to make a neckless (used a diamond bit). I've used it to cut holes in tile, a lot of small plastic works and more. It's a fantastic tool as long as you have a LOT of bits.

Oh, and I clean stuff with it too - small wire brushes can clean up rusted tools.

I'd not suggest using it to sharpen anything though.