Machinist Hammer
I've recently been learning to use a lathe. For one of my first projects, I made a machinist hammer. Although I didn't design the hammer, I gained valuable experience with most of the lathe machining operations. It consisted of an Aluminium handle, Brass base, Steel head and Nylon hitting surface.
In the future I might add a Copper hitting surface to the other side of the head, giving it the full functionality of a machinist hammer.