Not to start a grinder-vs-hand filing debate, but.........
I have an Oregon 620 grinder that I impulse-bought 2 weeks ago, still new in the box. I was going to return it because I was having a hard time justifying it, thinking hand results would be better. Maybe I should learn to use it and give it a shot instead of all these file guides?
I know that hand filing will produce more of a razor edge, and that makes sense for a knife. But for a cutter that's flying through hardwood, that paper-thin edge is gone in seconds. I would think getting the cutter shape right (and consistent!) is more important, and a grinder is pretty decent at that.