I have made the simplest dynamometer in the world. When I constructed them and used them to do experiments, I have found that I can make it better from construction and usage. I change the pitch from 1.0 mm to 0.75 mm. It makes low speed decrease the space between the upper and bottom parts. And change the M2 screws to 4 blocks and holes for easy construction.
I have found that print them one by one, you can get a better and precise shape. I use the small layer height, 0.2 mm, and fill density of 50% for PLA printing. The printing temperature is 200 C and the bed temperature is 60 C. All parts work very well for me.
Print Settings
Printer brand:

Anycubic
Printer:

All-metal Mega
Rafts:

No
Supports:

No
Resolution:

0.2
Infill:

50%

https://youtu.be/5VtycsVbPSI