scope:

This Standard covers requirements for square and rectangular parallel keys and keyways intended for both alignment of shafts and hubs, and transmitting torque between shafts and hubs.

Keys covered by this Standard have a relatively tight width tolerance. The deviations are less than the basic size. Keys with greater width tolerance and with deviations greater than the basic size are covered by ASME B18.25.3M.

The inclusion of dimensional data in this Standard is not intended to imply that all sizes described are production stock items. Consumers should consult with suppliers concerning lists of stock items.