3-inch microscope mount and focuser
Because I wanted a nice inspection scope head, but I didn't care for the big heavy boom stands they tend to come with. This mounts a standard 3-inch (76mm) head onto some 1-inch aluminum extrusion, and uses a piece of 1/4-20 threaded rod as a focuser.
The placement of the focusing knob would be fine on a binocular 'scope, but on the trinocular the camera port comes out right next to the knob, so it's a bit awkward. I'll probably change that at some point.
The bottom of the all-thread tends to walk and wander a bit in the bottom rail, so it could use a keeper of some sort. Maybe even a bearing, if feeling really fancy!
This is pretty solid at 20% infill, but it takes forever to print. If you want to use less infill, add chunks of threaded rod into the provided deep holes as reinforcement.