Problem: you have a threaded rod keeping things together. It is fastened in one end, hangs free, and fastened in another. If one end had been right threaded and one left threaded a [turnbuckle](https://en.wikipedia.org/wiki/Turnbuckle) would be the obvious choice. But not it is a regular right threaded rod.

Solution 1: Make one side swivel and the other grip the threads.

Solutions 2: Split the turnbuckle in two, with a swivel in between, and turn them different directions.