[TR] How do they manufacture gears?

[Barry Schwartz]

Jim,
Not really sure what you mean by "make", since that encompasses quite a few
processes but basically and very simply, they are designed with a few basic
formulas (which can be found in any machinists handbook) depending upon the
type of service the gears is going to be used for, then either cut or
molded (if plastic)  They are cut like any metal using a variety of
speciality rotary cutters, usually carbide, or in the case of ring and
pinion ground and lapped as a set.  if required the surface of the gear
teeth can be hardened (as in those used in most if not all automotive
transmissions)

That's basically it in a nutshell

************************original message******************************
Speaking of gears, perhaps one of you with a mech. eng. or 
manufacturing eng. background can explain how they make them?
Barry Schwartz
La Mesa, CA (San Diego)