Just for the record, and to answer the question, gears are specified in diametrical pitch, e.g. a 1" 20 dp gear has 20 teeth, the teeth per inch on a rack is irrelevent, as at some point the rack has to have a round gear engaged. (ref. http://www.sdp-si.com/D190/PDF/D190T25.pdf)

If you are going to be using gears, Stock drive products has a set of excellent catalogs, with extensive tech info on gears, and various drive systems. Worth far more than the $0 they charge for them...


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