A lead modification that makes the tooth slightly thicker in the middle of the face width than at its ends, typically by a few to tens of microns. It keeps the contact pattern off the tooth ends when shafts bend, housings distort or bores are slightly misaligned, at the cost of a little load capacity at perfect alignment. End relief, which only eases the last part of the face, is a milder version.
Pattern's walking to the end of the face under full torque, put some crowning in the grind and center it up.
Also heard as
- lead crowning
- lead crown
- crown
Related terms
Edge loading
Tooth load piling up at one end of the face width because of misalignment or deflection.
Helix deviation
How far a tooth's actual path across the face width departs from the intended helix, including crowning.
Contact pattern
The imprint left on gear teeth by marking compound after running, showing where and how the teeth touch.
Tip relief
A slight removal of material near the tooth tip so each tooth enters mesh smoothly under load.