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is this stepper ok

edited October 2017 in Egg-Bot

Hi I am piecing together an eggbot build from various bits and pieces and I have a couple of steppers I rescued from an old Roland plotter. They are both 0.9 degrees rather than 1.8 but I have already found this isn't a problem. I can't find data sheets for either motor. They both have four wires so i am guessing Bipolar.and they have the same colored wires as the KH series so I am guessing its worth trying connecting them up in a similar way. They are both Nema 17. The recommended motor in the BOM is a kh42hm2-951 from the same company mine are made by Japan Servo.
My first motor is a KP42HM1 -021 by japan Servo. The case length is about 34mm thick (1.25") and looks pretty similar to the recommended one although obviously is 0.9 degrees.
The other is a KP42EM1-014 and is only 21mm thick (0.8") this is quite a bit thinner and I am guessing a bit weaker.
When I look at Japan Servo's current sizes they dont do anything this thin in 42mm square (nema17) they do one in 39mm square which is stated as 78 mN-m The recommended motor has mN-m 197!
Do you think these motors are usable. Do you think the smaller one will have enough power and which stepper would you use it for the pen arm or the egg turning spindle? or would i be better off dumping both and buying some new ones?

Thanks in advance


  • Yes, they'll likely work, depending on what driver hardware you're using. If you're using two different motors, pick the stronger one for the pen motor.

  • I am using your board it seemed simpler than the arduino route. The original seemed the best route :smile:

  • Great. If you're using our board and software, you'll want to open up the "" file in your Inkscape Extensions folder-- it contains a setting in there "STEP_SCALE" that you can alter for this configuration (400 steps/revolution -- 6400 steps per revolution), so that you don't have to make any other changes for the motor resolution.

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