Right and Left Hand Spiral Bevel Gears:

A right hand spiral bevel gear is one in which the outer half of a tooth is inclined in the clockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear.

A left hand spiral bevel gear is one in which the outer half of a tooth is inclined in the counterclockwise direction from the axial plane through the midpoint of the tooth as viewed by an observer looking at the face of the gear.


Zerol Hand, ANSI/AGMA 1012-G05The designations right hand and left hand are applied similarly to spiral bevel gears, zero bevel gears, skew bevel gears, hypoid gears, and oblique tooth face gears.

In hypoid gear design, the pinion and gear are practically always of opposite hand, and the spiral angle of the pinion is usually larger than that of the gear. The hypoid pinion is then larger in diameter than an equivalent bevel pinion.