Hammer

Hammer is a well-known tool for supplying an impulsive force. The ordinary hammer consists of a head of steel mounted on a handle of beech or ash. The length of handle depends upon the amount of momentum required to be given up during impact. If the hammer-head is too heavy to be wielded by hand, other motive-power may be supplied, such as steam-pressure or head of water.

In many mines ore is crushed by heavy cylindrical vertical rods that are lifted by water-power supplied through a water-wheel and allowed to fall on the ore placed beneath. This is the principle of the shingling and tilt hammers used in iron works. The ordinary steam hammer (q.v.) has a vertical steam cylinder, the piston of which is forced upwards by steam-pressure and so lifts a heavy block of metal. This may be dropped on to the mass of metal placed on an anvil beneath, to be wrought into shape by repeated blows of the hammer.