What Is End Play?

 

Definition: End play is the act of the spindle shaft moving in an axial direction.

Excessive end play in a spindle is usually an indication that the spindle condition is deteriorating. It is generally caused by looseness in the bearing assembly.

This can be:

Worn bearings: Excessive wear in spindle bearings causes dimensional changes in the bearings themselves causing larger gaps between the rolling elements and the raceways. This is usually accompanied by audible noise, chatter on the part and inability to hold tolerances.

Loosening of a bearing nut: When bearings are preloaded they are held in place by a “nut” or similar object. If this nut loosens or backs off the bearings are no longer preloaded allowing the shaft to move in the axial direction. This is usually accompanied by audible noise, chatter on the part and inability to hold tolerances.

Capture: If end play happens immediately after the installation of a spindle shaft and bearings into the housing it is generally improper capture of the outer races. This can be checked by measuring the distance from the end of the housing to the outer race of the first bearing and comparing that measurement to the bearing covers shoulder measurement. The bearing cover should push on the outer bearing race when tightened down.

Some end play can be expected during the actuation of a drawbar. If the spindle shaft returns to the same position it was in before the actuation this is normal.