Making Worm Gears With Taps - BUSTED

G'day everyone,

This is a follow up to the worm gear cutting series that I made a few months ago. The process that I showed involved free hobbing the worm wheel. This is because I do not have a universal mill and dividing head, so this rather primitive method was needed.

In that video I was asked why I made a hob, rather than using thread taps to make the worm. I think this was asked so often because several popular videos show free hobbing, using regular thread taps, and the results are very similar to what I was able to achieve, using a correct 0.8 module cutter.

I have done a bit of further research on the topic and whilst I do think that there is merit to the method in some circumstances, there is often a lot of information missing in these videos which may mislead viewers into thinking that these are a equivalent replacement to a module worm drive.

They are very similar, but they rely on different formulas to achieve the gear size, and will yield different gear tooth shapes and pressure angles, which should be considered if you are planning on making them.

I am not making this as an attempt to rebuke these videos, I think there is merit to the idea, but it is important to consider all the details which will affect how the worm may behave.