A gear whose teeth are formed on a conical pitch surface, used in pairs to turn power through an angle, most often 90 degrees. Straight bevels have teeth that run straight toward the cone apex, spiral bevels have curved, oblique teeth for smoother running, and Zerol bevels have curved teeth with a zero spiral angle. A pair of equal-size bevel gears at right angles is called a miter gear set. Bevel pairs are sensitive to mounting position, so they are set up by contact pattern.
Straight bevel gear set on the drill head is chattering, pattern's running off the toe, so back the gear out a few thou and paint it again.
Also heard as
- straight bevel
- miter gear
Related terms
Spiral bevel gear
A bevel gear with curved, oblique teeth that overlap in engagement for smoother, quieter right-angle drives.
Hypoid gear
A spiral-bevel-like gear pair with the pinion axis offset from the gear axis, standard in vehicle drive axles.
Heel and toe
The outer, wide end (heel) and inner, narrow end (toe) of a bevel or hypoid gear tooth.
Contact pattern
The imprint left on gear teeth by marking compound after running, showing where and how the teeth touch.