Lightbulb sockets for Edison E27 lamps often have a thread on the outside, so that the socket can be securely mounted inside a lamp shade.

I have several spare sockets, but unfortunately they are mostly without any rings that screw onto the socket.

I have identified two types of threading that slightly differs. One has an outer diameter of 40.2 mm and a pitch of 2.4 mm. The other has a 39.0 mm diameter and 2.1 mm pitch.

Added a files for an E14 socket. The pitch is 2.0mm

The freeCAD source is included so that users can easily adapt the design to different pitch and diameters, if need be.

Using green filament, as shown in the photos, is kind of silly.