This is a design for a DAVLL solenoid cylinder. The magnet wire is coiled around the cylinder between two ridges on each half.
The two halves fit a standard 26mm x 80mm atomic vapor cylinder when joined together. The notch at the connecting end of each cylinder fits the nub in the middle of the vapor cell. Each half is designed to mount using a standard quarter inch optics screw (~7mm thread dia. and 10mm head dia.). The screw hole is accessible even with the vapor cell in place.
I designed this so it could be printed without the need for support material.
Important design note: The inside diameter of the female sleeve connector is 0.2mm larger than the exterior of the male connector. This is because I have noticed that the particular printer I'm using tends to print holes (but not exterior dimensions) slightly smaller than the dimensions specified in the CAD files. Whatever printer you use might be different, so adjust accordingly for a good fit.
See and edit on Tinkercad: https://tinkercad.com/things/6XzdNRMyl5A