Spur gear computations

[mklotz]

More good stuff from the bookmarks file... This time the subject is spur gears. This source has the formula for virtually every dimension associated with spur gears that use the diametral/circular pitch description.

https://www.engineersedge.com/gear_formula.htm

This one covers the formulae for so-called metric gears that use the module description...

http://www.micro-machine-shop.com/module_gear_data.pdf

This one duplicates a lot of the formulae mentioned above but has the advantage of supplying an online calculator that, given the gear descriptors, will automatically calculate a lot of the dimensions you'll want to know. It's down at the bottom of the page. Just above the calculator on the page is a short treatise on how to identify unknown gears; very useful when restoring old equipment.

Notes on Spur Gears

A note here...

One of the tougher jobs for the amateur is determining the pressure angle of a gear. I wrote a program to implement my procedure for doing this; it's available on my site under the name, GEARPA. Several accomplished machinists have used it and commented on it favorably so, while perhaps not perfect, it should provide help for a difficult job.