Height checker
thingiverse
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/565SxD9LuE4 I find I am fairly often checking the height of each side of my printer. Can be hard to see the marks on the ruler sometimes. Just insert the height checker between the motor and bearing block and drive the block down until it touches. This way you know both sides are the same height. I have made mine 68mm tall as that is a fairly consistent height I use. This can be changed to any height that suits your printer. Small tab on the side to help you hold it.
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