Use this Thing to change a unipolar 28BYJ-48 to bipolar stepper motor

thingiverse

I've used the versatile unipolar 28BYJ-48 stepper motor in numerous projects due to its affordability and widespread availability from online retailers like Amazon or Ebay. Although its torque is relatively weak, it can be substantially increased almost threefold with a simple modification that converts it from unipolar to bipolar. A detailed explanation of this conversion process, along with its benefits, can be found on the blog http://www.jangeox.be/2013/10/change-unipolar-28byj-48-to-bipolar.html. This hack requires prying open a plastic cover that shields the motor's circuit board, cutting an etch, and then replacing the cover. However, this process often results in damage to the cover and makes reattachment challenging. This innovative Thing eliminates the need for disassembling the motor by providing a sleeve that slips over its back. The sleeve features a hole designed to align with a 2.5mm drill, allowing you to cut a precise hole directly through the cover and into the etch. I recommend cutting the hole in the motor's cover first, then removing the sleeve, and using the existing hole as a guide for drilling out the etch. A minimal amount of pressure is required to remove the etch completely. To verify that sufficient etching has been done, test the motor with a bipolar driver to ensure it functions correctly.