Geo Hahn
Yoda
Offline
...Drilled centre part of bolt part way out. Got a good friend with lathe to turn a T shaped piece and installed it with a stiff coil spring. I removed a lot of, but not all, play. In my opinion it does not substitute a rebuild, but it is a worthwhile improvement...
I got one of those from Herman van den Akker though I do not know if he still does them.
As you say, not a fix for a tired unit but does help a bit if there is modest wear that makes adjustment difficult across the whole range.