Converting 28BYJ-48 Stepper Motor From 5-Wire Unipolar to 4-Wire Bipolar

I've always wanted to build my own X-Y table, initially to make a laser engraver [and now a CNC :)]. I've been getting parts for it one piece at a time and last weekend I ran into a sale in my favorite online shop and I said to myself this is it! I bought all the remaining mechanical parts [extrusions, angle brackets, etc..], I was going to buy one of the nema 17 motors but I remembered I have a pair of 28BYJ-48 lying around.

28BYJ-48

I ordered an arduino shield with drivers for bipolar motors, while planning the wiring it hit me - Dang!!! the arduino shield has 4-wire ports to connect to the motor while my 28BJYs has 5 wires!

I had to look for the datasheets hehe, so here's the spec sheet that I found online:

Full datasheet here

From the back of my mind i was expecting that the 28BJYs were bipolar motors but they turned out to be 5-wire unipolar motors!! Luckily there is a way to convert it to a 4 wire bipolar motor :) Its basically cutting the connection between the center tap of the Pink-Orange and the center tap of the Yellow-Blue winding. This connection can be found on the PCB under the blue plate cover.

This center tap is normally connected together through a PCB trace and goes out into the red pin. Cut the trace and viola! bipolar motors!

Here are more pictures during the conversion:

Note: the links to the parts contains my affiliate link from banggood