There are two different designs for the Restraining Bolt.
original BC version and the Arri-Type Restraining Bolt. Both are shown
image to open a 3D .pdf version of the Original BC version.
The drawings for the Arri-Type Restraining Bolt have not been
published. Click on the image to go to Astromech.net thread.
You can download models
of the Original BC version
in STEP AP203
(.stp) format in English (inch) units as well as in 3D.pdf format: