Key

A key is a piece of mild steel inserted between the shaft hub or boss of pulley to connect them together in order to prevent their relative motion. A key is always inserted parallel to the axis of Shaft. Keys form a temporary joint to transmit the torsional load from shaft to the connecting members.

Key can be classified as:―

1-Rectangular Sunk Key―A rectangle sunk key as shown in fig. is used where a stable connection is desired as in machine tool.

2-Saddle keys-There are two types of saddle keys―

(a)Flat Saddle Key-