Saxophone repairman Matt Stohrer of http://www.StohrerMusic.com isn’t quite sure what the preferred nomenclature is for the hinge rods that do double duty as a pivot screw as found on the Selmer Balanced Action and some versions of the King Super 20 and surely other models of saxophone, but he knows how to machine the shoulder back to take up mechanical slop and fit the key, and in this video he shows you how. DO NOT TRY THIS AT HOME. This video is intended to be explanatory in nature for consumers, and can serve as a viewpoint/reference for professional repairers.
Worth noting this is *one method* for fixing a very particular problem. For example, if the solid rod is very loose between the posts, I will swedge the rod to add length (there are a few ways to do this)- possibly in concert with the approach shown in the video above, which is equivalent to countersinking a pivot screw. When the receiver is so worn that countersinking won’t work or would require an extreme amount of countersinking, I will make a pivot receiver insert. If the post has been over-countersunk in the past, I will make a post bushing. Sometimes, rather than swedging a solid rod, I will make a rod extension.
In the case above, the solid rod was not at that loose between the post in my judgement, the pivot receiver was not that worn, just the screw did not extend far enough.
PIvot receiver insert and post bushing: https://www.youtube.com/watch?v=glpez2GRwX8
If you like this stuff, consider supporting me on Patreon: https://www.patreon.com/mattstohrer
Also check out the Open Source Saxophone Project: http://www.OpenSourceSaxophoneProject.com