The last nickel calibration test I designed gave no real feedback on how to fix the problem. This one should allow for measurements and corrections.

This one is exactly 21.21 mm wide in both the x and y. The slots are the same lengths (21.21mm) but a little wide (3mm)to disregard the width of the slot until the x and y are perfect.

Please like and upload photos of your made thing! I love to see this still working for everyone so many years later!

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