Worm gear – workshop calculator. How to quickly calculate the diameter and concave radius of the wheel?
Do you have a finished worm on your table and need to quickly turn a blank for the worm gear? Did a client bring a worm gear in pieces? Here is a quick cheat sheet with three formulas you need to punch into your calculator to start machining right away.
All calculations are made based on the axial module (mx) of your worm and the number of teeth (z2) that the gear wheel is to have.
1. Reference diameter of the gear wheel (Dp2)
This is the most important base dimension on which the next steps depend (this parameter is not essential for the lathe operator):
2. Tip diameter (Da2)
This is the diameter measured at the very center of the wheel, at the deepest point of the concave arc.
3. What radius to turn on the circumference of the wheel?
In order for the wheel to properly “envelop” the worm, you must turn a concave arc on its circumference.
Formula: The arc radius is half of the worm’s outside diameter (Da1) minus the axial module (mx).
4. Maximum output diameter (De2) – the “enveloping diameter”
This is the maximum overall dimension of the wheel – a dimension measured along the highest, outer edges (at the very corners of the wheel).
The simplest, safe workshop rule:
