i use a table top belt sander- very carefully, so as not to heat blade up- slowly- then use a stropping leather on the sander to give it razor edge- like the following but diff company, can’t remember name now- it’s down in the cellar- too lazy to go check lol
I’ve tried all kinds of different sharpeners- nothing does as quick and good a job as the belt sander- the ken onion is along the same line- but smaller- and i think it has variable speed too? which would be nice o n the belt sander model i use- The leather stropping belt is awesome- puts a mirror finish on blade edge-