I made this knife from a piece of 1 1/4" cable. Normalized it three times after forging to shape. Did not normalize after grinding but have been told this was necessary. Sanded to a 1000 grit finish, did the file work, hardened in oil that I pre-heated till it was hot to the touch. Brought it back to a 1000 grit finish then grinded the cutting edge into the blade without overheating it. I did not edge quench it I just submerged the blade only, straight down in the oil. There was not a crack till after I etched it in 140 degree F muriatic. While I was hand sanding with 1000 grit to highlight the etching I saw the crack. I am assuming this would not have happened if I would have tempered immediately after hardening. But, I am not sure. any suggestions would be appreciated. The crack is in the curve about an inch from the end