I bought 6 of these once that were dated early 80's. Half were reasonably easy to get a decent edge on with a coarse stone to start with and then working to finer stones to get a shaving sharp edge. About 30 minutes per knife. The other 3 I had to use files on to re-profile the edges and took a lot of work to make them sharp. They were Camillus and Ontario knives. I ground the top of the guard off on a couple of them which made them much better utility type knives. I put them in a couple of BOB's. and gave the rest away. There seemed to be quite a bit of difference in the factory edge profiles.