Elly Catfox 
nya
I like this image, but unless you're trying to dull your blade on purpose, you need to hold the blade at angle to the sander, probably 25 degrees for a sword, although I could understand 20 or 30 perhaps. There's a million tutorial videos out there if you need to see what I'm talking about. Personally I just do it the compact, cheap, and easy way with the Lansky sharpening system, but if you have the space for a belt sander that's cool.