Here is some addons for Mini belt grinder, that you can easy buy in many China e-shops. Just google something like Mini Electric Belt Sander Adjustable Speed Grinder DIY Polishing Grinding Machine Cutter Edges Sharpener 15/25mm Belt Sander
This is excellent tool for knife sharpening. I made some addons for 2.5 cm version of grinder, that make working process a bit easy and cleaner: