[jcc3inc]

Dear Sir:

There are better choices for rack and pinion. First, 20 degree pressure angle is a better choice for your apparent application. Second, with a smaller number of teeth, there is undercutting of the pinion; you need at least 32 teeth on 14 1/2 degree or at least 18 teeth on 20 degree gearing. If you expect to load the pinion into the rack, 20 degree runs much smoother.

You might consider 24 dp instead of 12 pitch. 12 pitch, 1" diameter has 12 teeth for 3.14159 inches travel. 24 dp has 24 teeth for the same travel. Note that 20 degree requires a min of 18 teeth, so you have accomplished what you want.

Regards,
Jack C.