Lock – nuts are sometimes referred as shaft or withdrawal nuts depending on the use on which they are to be put in. They provide a simple means of axially locating bearings and other machine components on the shafts and also facilitate mounting and dismounting small bearing on withdrawal sleeves. The required bearing internal clearness on tapered sleeves is achieved by carefully tightening of lock nut. For tapered roller bearing, the positive clearance is achieved by full tightening of lock nut and releasing by ¼ pitch.

The lock nuts are designated as ‘KM XX’ and for withdrawal nut it is ‘HM XX’