This eBook describes the easy and accurate way to make spur or helical gears using a table saw, scroll saw, or a router. It includes a spreadsheet dimension calculator compatible with Excel or Google documents (free) that gives dimensions according to AGMA (American Gear Manufacturers Association).
It also includes description of a shop-made jig for accurately and evenly dividing a circle into any number of increments without odd angles or cumulative error. Gears made with this technique reference the center hole to ensure gears are concentric rather than taking the risk of being off center. So much easier on the eyes and more accurate than the outdated method of sawing and sanding to a line on a glued on paper pattern. This technique can also be used to reverse engineer gears from paper patterns so they can be made more accurately.