In my quest for a self-contained toolbox style handle, I started with the handle from a Ghostbusters prop (thanks RyanTheMast!)

Inside handle width is ~4".

#6 fasteners runs through the pivot and are nutted on the other side. to provide as much strength as possible. There's enough clearance in the joint where you should have full screw thread engagement in the captured nut while still allowing the handle to rotate freely but YMMV.

Assembly Hardware: #6-32 socket head screw - 1" long: https://www.mcmaster.com/91251a153

#6-32 hex nut: https://www.mcmaster.com/96537a130

Attachment Hardware: #8 Flat head wood screw