Specimens illustrating the Woodruff keying system mounted on a wooden base board.

Patented in 1887 by W. N. Woodruff, this shaft keying system does not require so much skill as the feather type of key and keyway. The key consists of a half disc of steel. The keyway in the shaft is milled out by the special milling cutter which is the same size as the disc, but it is made shallower by the amount that the key should project. The keys are made in standard sizes. The objects comprise: An adjustable 'V' block showing use of the key in its screw to constrain sideways twisting but allow vertical movement; this is used to support the shaft during the milling operation; three keyway cutters; two shafts with various woodruff key sizes fitted; and a spare key.