I managed to do this with my Prusa i3 Mk2, believe me it was a lot harder with the threaded rod setup! Edit: It ended up being very beneficial as my printer is now fully a Mk3S except for the Y axis which is still Mk2 but with the removable bed. I can't run a calibration without modifying the firmware to account for the 10mm less z height, so it's good to know my printer is perfectly perpendicular and it doesn't matter.

Part of the skew is also going to include the angle of the stepper motors and the rods. You should also adjust the bed rods and move the bed to the extremes and adjust the screws there.

Just to share my experience - I tried the steps in the video but those checks were fine. I still had a 0.19 degree skew. I noticed if I loosened the Y axis smooth round rod holders then either pushed them up or down while tightening them back up, that would have an impact on the calibration result. My calibration was reporting the left was lower then the right side, so I tore a small piece of paper, folded it twice and put it under the round rod in the holder at the back corner just to raise the rod a fraction of a mm (probably 0.4mm). Finally the calibration result changed and it is now a 0.10 degree skew. That was without trying to fine tune it further.

Did as you shared the skew was reduced now it is 10 . Lower than previously and in acceptable range. Many thanks waiting for your next video

You saved me so much time!

Thank you for making this! I recently had my calibration go from perpendicular to slightly skewed and I had no idea what happened but, I followed along and sure enough, one side of the bed was off so, I loosened it all up, used the straight edge to keep it as in line as possible while I tightened it and BAM! Back to being perpendicular, and by a good margin at that, went from being a 0.14 to a 0.10

Following this has helped take my MK3S+ from a 0.13 skew to 0.09, thanks. I'm really looking forward to seeing your method for improving dimensional accuracy, perhaps it'll help solve the non-existent accuracy & print quality in my "factory assembled & tuned" MK3S+

I gave this a go after getting a 27 degree skew on my first ever printer build during initial calibration. After trying I got a failed calibration error twice while redoing xyz calibration but alas!, third time was the charm and perpendicular results. Hats off to you and great video.

Great " correcting XY skew for dummies". Just what I needed step by step guide. 🎉 Eagerly waiting for next video. Thanks 👍

Interesting video,I think you should share this on prusa Facebook groups

I didn't have square tool, so I just did the whole process by printing repeatedly some first level test. I somehow got a 0.04° skew, but I guess that was mostly just luck :)

Great video! I think you might have sold me a E3d nozzle a week ago lol

Where's your video on steps per mm correction? thanks

thank you my 3D printer is kalibrate:)

One of my Mk3 has 0.02 !!!!