ABSTRACT
The purpose of gearing is to transmit power and/or motion from one shaft to another at a constant angular velocity. The tooth form almost universally used is the involute, which has properties that make it particularly desirable for these functions. It will be shown that in order to attain constant angular velocity, the meshing tooth forms must have specific geometrical characteristics which are easily obtained with an involute system. Involute curve is widely used for gear teeth. This chapter looks at the generation of a gear tooth. It shows a straight-sided cutting tool, such as that used in the hobbing process, generating an involute tooth. The chapter illustrates the difference between spur and helical gears. It shows the relationship between the transverse and normal planes of a helical gear. Tooth thickness can be checked by measuring across several teeth with vernier calipers.
