This is a "quick" (near 30min) high precision test designed to test and calibrate your printer for dimensional accuracy and elephant foot.

All the measurements can be found in the image.

Procedure :

1. Check the bolt and nut height
2. Check the bolt base for elephant foot
3. Check the nut outer diameter
4. Check the nut top inner diameter (where there is no thread)
5. Check the nut top border width (where there is no thread)
6. Check if you can screw the nut, each thread has a 0.1mm tolerance

If you pass all the tests and you can screw the nut without effort you printer is awesome!

Extra step: Try to print it faster!!!

The steps I do to calibrate my printer are :

1. Calibrate E-steps
2. Calibrate bed using my quick test - https://www.thingiverse.com/thing:3898350
3. Calibrate flow using my quick test - https://www.thingiverse.com/thing:4641874
4. Calibrate X,Y and Z precision - https://www.thingiverse.com/thing:80126 or https://www.thingiverse.com/thing:2837841
5. Calibrate high precision dimensional accuracy using this test

I use Cura and the parameters I use to achieve the high precision are :

• Flow
• Wall flow
• Initial layer flow
• Horizontal expansion
• Initial layer horizontal expansion
• Hole horizontal expansion

Common problems :

• If you can screw the nut from the top and not from the bottom you probably have elephant foot
• If your screw parts have X,Y dimensions within expected and you still cant screw the nut freely you may have Z calibration problems, check the heights and screw pitch

Note: You can use a normal metal M12x1.75 bolt and nut to better test your print.

If you have more tips or tricks let me know in the comments!!!

Updates :

• V3 : Pitch tolerance increased to 0.12mm on both threads. Indentation added on both parts to remove the possibility of seam causing problems in this test.
• V2 : On V1 the pitch tolerance of 0.2mm was only on the nut thread. In this version the pitch tolerance is divided for both threads with 0.1mm for each one.

Enjoy and post your results!

If you found my Things useful, treat me to a cup of coffee :)