Captive Bolt

Print at 1.5 scale. It works, but it a little difficult to break free.

A 1/2" captive bolt with knurled faces. Print with support and do not scale smaller as you will negatively affect the spacing of the threads. Try scaling it lat least 1.5 because it's pretty hard to get it loose after printing at the moment. 1.5 worked fine for me but I will update the model after making a few changes.