Originally Posted by jiml
32, 48, and 64 pitch gears refer to the number of teeth per inch, if you could lay it out straight.
The 0.4 and 0.6 module gears are based on a metric measurment (not sure exactly how it goes). So a 0.4 gear if you converted it would come out to something like 62.3 teeth per inch, which is why you can't use it with "standard" gears.
No! Pitch refers to the number of teeth the gear would have if it was 1-inch in diameter. A 1" diameter 32 pitch would have 32 teeth. A 1" diameter 48 pitch gear would have 48 teeth. etc...
Metric Module measures the height of running face of the gear tooth perpendicular to the center (also called the addendum). In an 0.4module gear, the running or contact face of the tooth is .4mm high...