Awesome project by the way I've had a blast working on it. I'm closing in on my first successful run but I seem to be having difficulty getting it into alignment. with every new line it starts it shift over and up and I don't seem to be able to make any changes that can mitigate it.

Any help here would be really great.

# *** Polargraph properties file ***
#Thu May 18 14:16:52 EDT 2017
controller.pixel.samplearea=30
controller.pictureframe.position.y=182
controller.pictureframe.position.x=256
controller.testPenWidth.startSize=0.5
controller.machine.colour=969696
machine.motors.mmPerRev=110.0
controller.window.width=1242
controller.frame.colour=C80000
controller.image.position.y=175
controller.image.position.x=248
machine.motors.accel=400
controller.image.height=300
controller.machine.serialport=0
controller.window.height=598
controller.maxSegmentLength=2
controller.geomerative.polygonizerLength=1
machine.penlift.up=180
machine.penlift.down=90
controller.page.position.y=150
controller.vector.scaling=100
controller.page.position.x=196
controller.pictureframe.width=431
machine.step.multiplier=1
controller.grid.size=25.0
controller.testPenWidth.endSize=2
controller.pictureframe.height=284
controller.page.colour=DCDCDC
controller.testPenWidth.incrementSize=0.5
controller.image.width=450
machine.motors.stepsPerRev=400.5
machine.pen.size=0.8
controller.page.width=554
controller.pixel.mask.color=00FF00
controller.machine.baudrate=57600
controller.vector.minLineLength=2
machine.width=946
controller.geomerative.polygonizer=1
controller.page.height=355
controller.vector.position.y=0
controller.background.colour=646464
controller.image.filename=H\:\\Project\\nicolas_vector_by_deto15.png
controller.vector.position.x=0
controller.homepoint.y=150
controller.guide.colour=FFFFFF
machine.motors.maxSpeed=500
controller.homepoint.x=473
controller.density.preview.style=3
controller.pixel.scaling=1
controller.densitypreview.colour=000000
machine.height=688

I am using the AFMSv2 if that matters

I'll try and upload a video of its misadventures to give you a better idea of what is going on.

This is what my machine believes a square looks like... comical and frustrating...

Great, thank you Sandy this gives me a good place to start I was stumped. To be honest when it came to the power I'm a bit clueless...
I'm using these Adafruit Steppers:
https://www.amazon.ca/gp/product/B00EYIFW70/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

and I'm using this PS:
https://www.amazon.ca/gp/product/B01BQUS8MY/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1

Am I under powering this thing? I worry about it bursting into flames if I get the power wrong.

Just tested with the 12V DC 1A PSU to no avail. The result was exactly the same as the previous runs. Back to being stumped.

On the bright side it didn't burst into flames... mind you it was only running for a few minutes for the test.

Edit: I also reduced the gondola weight significantly as well as the counter balance weights.

Thought: The bead spacing and sprocket spacing don't line up well... could this cause these kinds of indescrepencies?

It's been awhile due to frustration but I'm back at it again.
Same problem although torque doesn't appear to be the issue.
I've lightened the load to nearly nothing and a test area down to 800mm x 500mm which is quite small...

In the back of my mind I've been wondering if its possible one or both of these motors is damaged... of the 4 screws in the back of the motors I have removed the top two and screwed them in from the front instead of the back for the mounts. would this affect or possibly have damaged the motors in any way?