[jyl]

Sure you can sharpen stamped knives. Most of my knives are stamped steel, Victorinox Forschner, very good knives for the money. They can be made very sharp and can take a 15 degree edge, though they do need frequent attention at that angle.

If you're talking about a serrated edge, that is a different story. They can be sharpened but not with the usual technique on a stone. You can do something on a stone - hopefully not a nice stone - but I think its more of a grinding wheel job, personally. I don't use serrated knives except for bread, so my knowledge there is limited.