What is a multiple threaded worm?
In the case of a worm, the number of teeth (as used in ordinary gears) is called the number of starts.
A worm with two or more starts is called a multiple threaded worm.
Increasing the number of starts on the worm, in other words, using a multiple threaded worm, increases the efficiency of the power transmission. Also, as shown in the following two examples, when the number of teeth on the worm wheel is the same (but the twist angle is different), the worm with the larger number of starts has a smaller reduction ratio.
Example :
Number of teeth on worm wheel: 30
Number of worm starts: 1
Reduction ratio: 30:1
Number of teeth on worm wheel: 30
Number of worm starts: 3
Reduction ratio: 30:3 or 10:1
