A belt sander definitely has its place in tool sharpening. That's all I used for years. Last fall I picked up a low speed Rikon grinder and a Wolverine jig system. I can now sharpen my "roughing" gouges in a matter of seconds, remove less steel and have a sharper, consistent shape than I ever could before.
I found another trick that helps me touch up the edges on my skew gouges and my "beaver". A word of explanation - I used to use a parting tool to remove most of the wood from the inside of a pot. Last year I started using my skew gouge and cut my time significantly. This season I ground a thick "skew" gouge from a cheap set of tools to have a 90 degree edge on the end of the tool. This tool cuts straight on, like a parting tool would, but removes much more stock at a time. Kept sharp, it cuts ribbons out of a pot internals with great results. Back to the trick of sharpening them... I started using a pocket diamond sharpening stone for pocket knives to touch up my skew gouges, one high speed steel, the other has a carbide tip. The diamond surface WILL sharpen the carbide tipped tools. I use a "detailer" from Penn State and have not replaced the carbide insert since I bought it 3 years (and around 1,000 calls) ago. I just picked up a 2"x6" diamond stone with a different grit on each side.
