The microscope objective lens uses a 0.8×1/36-inch RMS thread:
https://en.wikipedia.org/wiki/Screw_thread
https://threadingtoolsguide.com/en/blog/thread-in-microscopy-the-microscope-object-thread/

At first, it seemed difficult to print the microscope RMS nut thread on an FDM 3D printer:

• FDM 3D printers usually stack layers horizontally with a layer height of 0.3 mm
• For coarse-threaded screws, such as M12×1.25, this is usually not a problem—please refer to my
  https://www.thingiverse.com/thing:5404145
  But what if the thread pitch is only 0.7 mm? Is it really an impossible task to complete?

Solution:

• In each layer of FDM printing, only the part of the layer that intersects with the thread is printed, and this must be done within a certain vertical tolerance range.

I haven't conducted a patent search. If there are relevant patents, they should be respected; if not, my idea has entered the public domain.

As always, I have attached the OpenSCAD source file for you to modify and optimize as needed.

The attached Microscope_RMS_thread_ring.stl file is only used as a test case, assuming a layer height of 0.3 mm. You can adjust the layer height and other parameters

The attached Microscope_RMS_thread.stl file

Please also check out my other designs:
https://www.thingiverse.com/thinger13/designs