Excess backlash and looseness across a drive, from worn teeth, worn bearings, loose splines or sloppy couplings. On machine tools it shows up as lost motion on the handwheel and poor positioning; in vehicles as clunks on throttle changes. Slop is usually measured as total free rotation at the output with the input held.
Heard on the job
There's a quarter turn of slop in the rotary table, the worm has worn a pocket in the wheel.
Also heard as
- play
- free play
- lost motion
Related terms
Lash
Shop clipping of backlash, the free play between mating gear teeth, as in set the lash or check lash.
Backlash
The play between mating teeth: how far one gear can rock before its teeth contact the other gear's teeth.
Clunk
A single heavy knock when a drive takes up its backlash on a load reversal, such as on and off the throttle.