A cartridge for a machine tool is provided. The cartridge has a main body,
two punch-retention arms, and two die-retention arms. Preferably, the two
punch-retention arms are spaced apart and at least generally parallel to
each other. Likewise, the two die-retention arms preferably are spaced
apart and at least generally parallel to each other. In some cases, the
main body is formed of a first metal, and the punch-retention arms and
die-retention arms are formed of metal(s) different than the first metal.
In one group of embodiments, the invention provides a cartridge having a
weight of less than 3 pounds.