Rack & Pinion Calculation

[diabolical7]

I tried using the search function but to no avail:

I'm trying to calculate deg/mm for a rack and pinion
but I am not sure how I can do this please advise

[ger21]

The pitch diameter of the pinion is how far it travels in one revolution. Divide that by 360 to get mm/deg. Then take the inverse to get deg/mm.

[jpgdesigns]

for a little more info: http://en.wikipedia.org/wiki/Gear#Pitch

[diabolical7]

pitch diameter is the distance from the end of one tooth to the other right?

[Al_The_Man]

The pitch dia or pitch circle is used to calculate the distance the centre of the pinion would travel in one revolution. It usually falls below the tip of the pinion, at roughly half to one third the height of the tooth, depending on pitch angle.
If you go to any of the gear manuf. they should show the description of all the terms.
Boston Gear, Martin, or the free set of data books from SPI/Stock Drive Products.
Al.