Thread: worm gears

I need to make a worm gear. I have the gear it drives, the distance between centers, the number of teeth the other gear has, I can figure out the diameters, but I'm having trouble with the pitch. How do I calculate the pitch of the worm gear? Anybody have a formula for me?

I think that the distance between centers will be the pitch, from what I can see in these drawings.

worm gear design - Google Search

It looks like you just make the worm to mesh with the gear proflie.

Number of teeth plus two divided by mic O.D. works good on spur gears. May come close on a worm wheel.

Example:

32 teeth, 2.125" O.D.
34 divided by 2.125 = 16 DP

Not all are DP based though - just as easily could be circular pitch

Is worm single start?

Probably come close to circular pitch measuring tooth corner to next tooth corner on worm. Circular pitch times number of teeth on worm wheel must match circumference of pitch dia.

I can't claim to understand all the pitch systems, perhaps I can take this opportunity and someone can explain why diametral pitch is a specific threading system on (some) lathes?

On edit: I found this: What is the definition of diametral pitch?