Not exactly a engine, but I figured I would post this hammer I just completed. Head is made with W1 steel that was hardened and tempered. Handle is made with 1018 Steel. I tried it out once and Im already in love with it! I might try and sell it, since Im jobless now. For some reason when I hardened the head, a bunch of deep scratches appeared. The part was scratch less before hand.. I really wanted a deeper blue, but I got impatient. I used a small kiln to harden the head, but I threw in some charcoal to make sure the internal carbon didnt go anywhere.