Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
I have 4 of these unidentified parts and I'm not sure which set the originally came from (stud shown for comparison). Any guesses would be welcome!
Those are Wheel 8mm D. x 6mm
In brown they were often used as wheels for cannons on sailing ships or castles.
Required, but never shown