This post will refer back to the thread in which a water hydrant head was repaired at Wheaton Labs:
https://permies.com/t/276448/Extracting-Headless-Bolt
The entry photo on that thread is pasted below to start the discussion and questions. That hydrant is a Woodford and uses a set screw to enable the operating handle to raise and lower the rod that allows water to flow when open and not flow when shut off. The set screw allows adjustment of the rod (yes??...no??) along with what appear to be other adjustment points.
Our hydrants are Merrill, from the 'Anyflow' models. Photos accompany to illustrate the difference in the mechanisms between Woodford and Merrill. The Merrill uses a sliding pivot connector (not threaded) over the rod, the latter generously threaded at the end. The pivot connector is sandwiched by two adjusting nuts so that you can adjust both up and down to find the 'sweet spot' on water flow and water shut-off. Panel 1 shows this pivot connection with and without the draw straps: Two metal draw-straps engage with the pivot connector at one end of the straps and with the handle lift points at the other end of the straps. Thus, lift the handle and the straps pull on the connector to raise the rod for water flow as shown in Panel 2.
The problem can be seen when all is intact: The adjustment nuts are not very accessible (the top nut not at all!). So adjustment of flow is a PITA! You must dismantle the whole head set-up with each small turn of an adjustment nut and reassemble just to see if you met with success. Very laborious! Was wondering from those with experience if it would be possible to drill and tap threads through the pivot connector so that it could accept a set screw and operate more like a Woodford and similar hydrants...? Note that the 'Parts' photo shows the pivot connector being silver in color and that the same on my hydrant is corroded from exposure to the elements. Would it be better to find the same or similar part in brass or an alloy that was rust/corrosion free? Would there be a set screw with similar corrosion-free properties when screwed into the pivot connector? Success here would save me a lot of time and may be of use to many other hydrant users. Thanks!