Update 2024:

I improved the design of this case a bit by adding material in weak points to increase strength, and adjusted the size of the cap to be more forgiving for the inherit dimensional inaccuracies of most printers. Also adjust position of the threads to make it easier to get the cap on and lowered contact time so it's quicker to screw on and off.

Original:

We didn't have any more of the very wide objective cases in our lab, but I needed to safely store them as I used other objectives. So I designed this case, which can safely store even the widest of Olympus objectives (or other objectives that use the similar Royal Microscopy Society thread standard) and is easy to print.

I printed mine at 0.12 mm layer height on my Ender 3, with AMOLEN matte navy blue filament and it came out incredibly smooth and the threads fit extremely well.