I’ll touch up a chain with a file in a pinch. Have jigs but don’t use them. Just the little clamp on guide. Like sharpening a knife. Get a good angle and keep it. I grind chains. I take care of a friends chains with an orchard. Used by workers who don’t care. They get rocked a lot.
And once you got grinders set up right a 20” chain takes maybe 5-6 minutes. And if you got the angles right and know how to grind......it’s sharp. If you don’t know......don’t cut very well.
