As others have pointed out they will need to be carefully resharpened. Getting this right requires at least a bench grinder and a set of coarse to fine whetstones, as well as a fair amount of skill. I knew this was happening but was still a little surprised at how much metal had to be removed to get the right angle. If you have the appropriate tools, you should allow at least an hour for each groove. Once properly shaped and sharpened they make a very handy chisel set.