This thing has been my go to test design, in the early days of 3d printing for me it proved to be reliable.
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com
I made this Cog to be used on my TK armor Husky tote.
I did not create the cog, I unfortunately do not have the source to attribute for this image, sorry.
I will not be responsible for injuries do to use of this design. Please Tinker responsibly.