Quick model to help calibrate rotation distance as I had to do it on a ton of printers at a time. 

Has a groove to keep the filament in line. 

From the bottom of the ruler to the bottom edge of the “nub” on top is 100mm. 

Each arrow is 10mm from each other, the pentagons are at the 5mm mark, and then there are small markers each mm up to 20.

I printed with a .6mm nozzle to the details kind of bled into each other so I'd recommend .4 or small if you want crisper details but it still worked fine on a .6. I liked have a color swap just for more visual clarity.