## Rack and Pinion Gears

I have looked everywhere to try and find how to calculate the distance a rack will move.

I have a mechanism where every revolution of the pinion, the rack will move one direction, then it will move back in the opposite direction. So I assume the ratio will be 2:1, every one rev the pinion does, the rack will move forward, then return. I can find loads of material on gear ratios etc, but nothing on how to work out the distance a rack will move depending on the wheel diameter and No. of teeth.

Or do I just use standard gear ratio calculations? Such as this: http://www.schsm.org/html/gear_ratio_calculations.html
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 Blog Entries: 2 Recognitions: Gold Member Science Advisor You just need to know the tooth pitch of the gear/rack, and the number of teeth on each. Given these numbers, one revolution of the pinion will move the rack (x) teeth, which you can convert to distance given the tooth pitch (teeth/distance).
 At it's very basic level 1 rotation will mean a linear movement of 1 circumfrence. 1:1 ratio. I'm guessing that wasn't the question you were asking though. I just thought i'd say it just incase this was a 'wood for the trees' problem.