This is a fully 3D printable lock, no screws required. It is easy to assemble and it works very well.
It can be opened form the outside by removing the cover, so this lock should not be used for security.
To assemble put the longer end of the gear shaft through the inside cover and glue on the handle. Then put in into the door, and attach the outside cover. Put in the lock shaft, and put on the front cover.
This lock is meant it fit in a door with holes of diameter 38mm.