Fig. 115.
The Adapter.
Fig. 116.
The Adapter.—For the attachment of wheels or other rotating pieces to the shaft an adapter is employed ([Fig. 116]). It is bored with a ¾" hole to fit the shaft, and the external diameter is 1". At one end is a shoulder through which the binding screw is tapped, and there is a nut and screw at the opposite end. A feather will prevent the wheel from turning round on the adapter which is itself made to revolve with the shaft by screwing the binding screw down on the shaft. Some adapters are only large enough for a single wheel 1" thick in the boss, but it is useful to have others that will take two wheels. Adapters are shown in use in [Figs. 46] and [101].
The Lever Arm.
