I'm changing the knives in my planer. The old ones had too many knicks. I bought a set from a big name blade company. When I openned the package, I was disappointed with the coarse grinder marks they showed. The backs especially looked like they were too rough to be really sharp. They look just like most chisels do straight from the factory. I expect to have to finish the sharpening job on those. But I thought jointer knives were ready to go? I've seen a lot of discussion advising against trying to sharpen these knives at home. Am I looking for unreasonably sharp blades?