If you make this hammer, how long are you going to make the hollow head and what diameter? It would be good to measure some of the larger ones (4--10) pounds. The shot goes to the back on the swing start and lands on the face on blow contact. A sledge dead blow requires a lot of stamina to accomplish much work. Mine is a rubber head 4 lb. I used it to BUMP pins from aircraft landing gears. The 10 lb for breaking loose large nuts. They separate men from boys I often wondered which I was!