Roller diameter

Can someone tell me the Diameter of PRO NEMA 34 Roller Drive Spindle? please help. Thank you

1/2" I think. 12.7mm in metric. But from the website;

  • The R&P system is based on a pinion with a 1" pitch circle. The total linear distance traveled per revolution of the pinion is thus 3.14159". With the 3.2:1 reduction, this means that the distance traveled per motor revolution is 3.14159 / 3.2, or 0.9817". If you have a stepper with 200 steps per revolution, this means you have 200 / 0.9817" = 203.718 steps per inch, or 0.004908" per step. With 10x microstepping , you would have 2037.18 steps per inch, or 0.0004908" per step.
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I’ll agree with the web site. The drive pinion is PI inches per revolution and 20 teeth; the rack has 20 teeth per PI inches, or about 0.1571 IPT. Just less than 4mm (3.9898mm). Learned this the hard way :wink:

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Thank you for your quick response, however, I would like to know the larger diameter of the Aluminum gear not the pinion.
Best regards

according to my notes, those are 5GT gears, the one on the motor is 20 tooth and the larger one 64. So 64*5mm = 320mm circumference, or 101.9mm pitch diameter Actual OD might vary, but a quick check with a ruler says I’m close :wink: