Although it is somewhat less directly related to our hobby , this article is so interesting to read.
http://users.picknowl.com.au/~gloami...q9325rev7.html
I made a small 32 tooth brass gear last year at the TAFE ... it was for the threading dial on my lathe .The teacher went through the process with me . We used a fancy universal milling machine with digital readout. And a dividing head .
MIKE