I would not use a belt sander to sharpen a knife or a grinder. The reason being is that using anything high speed to sharpen a knife causes a blade to heat up (even if it dose not seem like much heat) changes the temper of the blade. 8 times out of ten at the tip and may cause the blade to break when it should not.

I prefer my Arkansas stone to anything else, just a preference I know. I too have used the bottom of a ceramic cup for a quick touch up and love the Lansky system but only use it on knifes I get in dire need of a good sharpening.

I would like to be bold and make a suggestion. Get the knife professionally sharpened,
Then get a ceramic rod to touch up or what I use is a leather strop on a flat board with the white risen. It keeps my knife like a razor. A good blade will stay sharp a long time even with use between sharpening.

Out of curiosity what kind of knifes to you guys own? I have many but use an Old Timer for a pocket knife and a Gerber clip knife (made in the USA) daily.

Respectfully,
Sean