Laying my cameras and lenses on the shelf a) made a crowded, messy array and b) left too much unused space above. Some sort of rack was needed, but it had to provide straight access to cameras and lenses. A carousel was the answer.
The cover photo shows the carousel loaded with four lenses at the bottom and four cameras on the upper deck. One virtue is to make use of the otherwise empty space above. A second virtue is, as a carousel, it presents the chosen camera or lens at the front, reducing the chance of knocking a lens or camera to the ground by pulling out something from the back.
In the separate-parts image, left to right the parts are: 1) Lower Race, 2) Spider Ball Cage, 3) Upper Race with Lens Tray 4) Posts and Pins, and 5) Camera Plate. The quarter-inch (about 6 mm) steel balls are trapped in spherical spaces with centres slightly below halfway thickness. This makes the opening slightly wider at the bottom, and so balls are inserted up into the spaces with a little force from below.
One image shows the assembled carousel empty: Among glues that would work, my first choice is gap-filling CA glue, second, a quick setting epoxy, and third, a hot-melt adhesive.
Unless your camera equipment is identical to mine, stl files are of no value. I'm supplying instead the source OpenSCAD files as these can be modified to suit your needs. If this forces you to learn OpenSCAD, then I apologise at the moment but acknowledge your eventual gratitude.
The author marked this model as their own original creation.