Borrow Round-head sledge hammer

The round-headed hammer is commonly known as a ball-peen hammer. It is primarily used in metalworking and for various tasks requiring striking or shaping metal. 

Uses of a Ball-Peen Hammer:

Peening: Surface-hardening metal by impact. 

Striking: Used to strike punches and chisels, typically with the flat face. 

Shaping Metal: The ball face is useful for rounding off edges of metal pins and fasteners, such as rivets, and for shaping metal, including creating arc surfaces in car plates. 

Forging: Particularly useful in blacksmithing for moving metal and creating decorative elements like scrolls or curls, and for refining details.