Hobbing Worm Wheel - Need Help

[LMMasterMariner]

Need to know diameter of worm wheel for the following numbers of teeth: 30, 32, 36, 40
for worm dia 24 mm x metric trapezoidal thread TR3

Even have plenty round bars of phosphorus bronze in various diameters wouldn't like
to use hit and miss approach.

Many thanks in advance / Best regards
LMMasterMariner

[olderdan]

Need to know diameter of worm wheel for the following numbers of teeth: 30, 32, 36, 40
for worm dia 24 mm x metric trapezoidal thread TR3

Even have plenty round bars of phosphorus bronze in various diameters wouldn't like
to use hit and miss approach.

Many thanks in advance / Best regards
LMMasterMariner

Found this in Engineers Handbook which may help.

Not sure of your method of cutting these but if free hobbing you need to gash the teeth first.
I think I would try a test on plastic or alloy to prove, good luck.

[LMMasterMariner]

Thanks Olderdan.

I also found some info in 'Handbook of Machining and Metalworking Calculations' and 'Machinery's Handbook 29th Edition (2012)' which I have in my pdf collection.
Yes, my intention is to use free hobbing method.
Already made hob from s.s. 304 24 mm dia hex rod. At the same time on the same rod made worm.
Here is picture of that and also picture (found on the web) of what hob should be when I finish it.

Best regards
LMMasterMariner

[viking]

O/D=(n+2)×mod