Threaded Pushrod
I threaded the pushrod all the way to the point where its diameter changes. That's necessary. In this picture, you can see the flat-topped threads that result. This part of the shaft is 9.3 mm in diameter, not the full 10.0 that I'd like to have. (In fact, these threads turned out to be a little shallow, so I recut them deeper. The situation is better than this picture implies.)