This is a suite of flow and tolerance tools.

All to be printed with a 0.4 nozzle at .4 line width, .2 layer height. 

First the cube where you have one of each thickness wall: .4, .8, 1.2, 1.6mm.  You print it, you measure each wall with a caliper, adjust flow and reprint, re-measure, rinse, repeat.

Second the tolerance ring (with built in chamfer bottom edges): you print it, and try to move the knobs.  Each knob has a different gap between it and the center ring, from 0.10mm to 0.30mm.  It’ll tell you what tolerances your printer can print at (the second photo of the ring shows my printer can't currently do less than .20mm)
You also have each individual section of this ring, in case you really want to dial it in, and don’t want to reprint the whole ring.  

I mostly kinda copied other tools that are out there, for the challenge of designing parts for myself, but this is the only place, I believe, where you can have all these tools/prints together. 

Also provided are the fusion 360 CAD models.