Remodel / copy of burhop's design using my path extrude script. A slice of the nut has also been taken out to make the internal mechanism more obvious.
The half-size version is reduced in size with a slightly steeper angle, but has the same printing clearance between the nut and bolt.
Printed full-size model in HIPS with 4mm clearance. Some cleaning of screw threads was required to get it to turn