I had made a nice skinner from some "mill finish" D2 I bought at Jantz Supply and I put the handle on and started the final polish with a small buff with 1500 grit diamond compound and was just polishing it lightly to just "brighten" the blade and a small pit appeared. I stopped and rubbed it to see if it was a piece of grit stuck in the metal. It felt like a pit and wasn't sticking up. I kept polishing and the pit became a hole. I've never had this happen, has anyone ever found a small bubble in their metal? It was about 0.025 big.
Ruined the blade as it was down near the base. My skinner is now an experimental oyster shucker.