The portion of a gear tooth surface that lies above the pitch circle and makes active contact with the mating tooth during operation. In broader shop terms, it also refers to the entire axial width of the gear blank, known technically as the face width. The condition of the face dictates the load distribution and noise characteristics of the mesh.
Check the contact pattern on the drive face to see if we need to adjust the pinion depth.
Also heard as
- Tooth face
- Face width
Do not mix it up with
- Face gear: Face is the tooth surface or gear width, while a face gear is a specific gear type with teeth cut on the flat end of a cylinder.
Related terms
Face load factor
A rating factor that raises calculated stress to cover uneven load distribution across the face width.
Contact pattern
The imprint left on gear teeth by marking compound after running, showing where and how the teeth touch.
Drive side
The tooth flank that carries load when power flows in the normal direction; the opposite flank is the coast side.