A ball-peen or ball peinhammer, also known as a machinist’s hammer, is a type of peening hammer used in metalworking. It has two heads, one flat and the other, called the peen, rounded. Besides for peening (surface hardening by impact), the ball-peen hammer is useful for many tasks, such as striking punches and chisels (usually performed with the flat face of the hammer). The peening face is useful for rounding off edges of metal pins and fasteners, such as rivets. Today we are looking at a military marked example:

This hammer has had the handle cut down by about three or four inches. This is not an uncommon modification and in this case was clearly done many years ago, presumably to make it easier to use the hammer in a confined space.

The metal head is forged from steel and has a flat and a hemispherical face:

It is on the opposite side of the hammer that the /|\ mark indicating military ownership can be found:

A hammer such as this would have a multitude of uses in a military context where there was a constant need for metal working skills to fabricate or repair items of equipment. This hammer has clearly had a hard life, but is the first example I have found to add to my little collection of military marked tools.