Generic 3D Bolt with Nut and Optional Washers

REVIT 2023

3D bolt family with parametric diameter and hole length. 

You can also turn on and off the washers, but keep in mind that the hole length parameter assumes they are there.

All the other dimensions are scaled from a 3/4" diameter A325 bolt, which was good enough for my purposes. Don't try to change other dimensions or things will break.