9. Diametral pitch (DP)

select a cutter. The only way to select a cutter is by sight.

Get a large selection of bevel gear cutters, then match

one of them to the side of a good tooth.

To find the amount of setover, first establish the

circular pitch angle

One circular pitch equals

360°. Therefore, you can divide 360° (one circular

pitch) by the number of teeth (NT) to find the circular

You can solve for the amount of

pitch angle

setover by using the triangle in figure 14-26, view A.

If you buy a stub tooth gear cutter, you can

manufacture a straight or helical stub tooth gear by

using the procedure you use for spur and helical gears.

If you use a fly cutter, use the old gear as a pattern to

Where the root radius is the outside diameter (OD)

grind a single-point tool bit to the desired shape.

divided by 2 minus the whole depth (WD).

A properly fitted gear must have a setover and a

depth increase. You should calculate these after you

14-28