Making screw caps and nuts

[ivla]

Update: making nut with thread generation script from there.
(orange is a selection color here)

Make thread object with "internal" (it's important!) thread


Select upper face and extrude it by Y (not by normal!)


Flatten upper face


Deselect upper face, select lower and extrude by Y


and flatten it


Select both upper and lower faces and inset it


and scale it radial by Y to the desired size (you can also use Absolute scale for it)


Bridge upper and lower faces, you get an "inverted" object


Select whole object and invert it


Both ends of thread looks like here: