Berg Anti-Backlash dbl Thread Pin Hub Gear AW64BS29-D50 and W64S-4D  Worm  [CJR]

This Anti-Backlash gear has 50 teeth and the mating worm gear has 2 threads per revolution, so it gives a drive ratio of 1:25  Anti-Backlash gear turns to worm gear turns.  The gear teeth angles and friction are such that the worm gear can drive the Anti-Backlash gear, but in the reverse direction nothing moves.

StyleDOUBLE THREAD PIN HUB
Part NumberAW64BS29-D50
TypeANTI-BACKLASH WORM GEARS
MaterialBRONZE QQ-B-637 ALLOY 464
Module/Pitch64
Bore1/4
Teeth50
Pressure Angle20
AGMA Quality10
OverallLength7/16
Face Width1/8
Pitch Diameter0.781