Look at the head and see how much blade is protruding out. I have a Delta planer that has reversible blades and there is so little blade protruding I think you could only sharpen it once and that is if it didn't have any nicks in it. I'm not sure if I would want to do it anyway so I keep buying new knives.Can porter cable planer blades be sharpened? I have a very inexpensive porter cable planer that has reversible blades. I am at least 40 miles to the nearest place to purchase unless I use amazon. Has anyone ever sharpened these blades successfully?