gear torture test

I wanted to know if a 3D printed gear can hold more torque than a Nema 23 stepper and which gear design and material is suitable.
So I designed this destructive test to get some understanding.

Here you can see my tests: https://youtu.be/Ik0hf_iBz6g

For me it was enough to know that the PLA and PETG gear I wanted to use can handle 9 to 12Nm of torque which is 4 to 6 times the holding torque of the strongest Nema 23 stepper I can find(2Nm). So if torque exeeds I will loose steps but not damage my gear (at least for static loads).

By the way I decided to use PETG beacuase it can handle the torque and I expect a better perfomance than PLA if friction increases the temperature.

Surprisingly the ABS Version failed quite early. I assume this is a bad quality ABS.

If you whant to test it by yourself you need:
- a hanging scale (>20kg)
- some strings
- 3x M5x50 (recomeneded DIN 603carriage bolt)
- 3x M5 nuts
- a camera

To calculate the torque:
t=0.1m* weight on the scal