I don't have an action shot of me playing it, but I do have a couple of pics.
Joe and I talked about the valve linkages. To meet our meeting opportunity, he had collected bits at a hobby shop to cobble together minibal links, given his late discovery that the S links were unsalvageable. (He did give me the old S links.) The 3mm screws with nice round heads were great, but the washers weren't a great fit and therefore he couldn't crank down on them as much as he might have otherwise. So, they were just tight enough not to wiggle around but any tighter and the slightly oversized plastic damping washers would bind on the ball end. He secured them using a nylock nut in the clevis gap of the old-style stop arms, and spaced the ball end out enough to clear the stop-arm screw using thick washers made from cutting aluminum tubing. This was serviceable, but, as he predicted, needed a better fix.
He simply ran out of time to make it better, but then he knows me and knows I could deal with it.
He suggested, as you can read above, replacing the stop arms with the chunky style stop arms from Miraphone that put the ball at the same level as the stop-arm screw, rather than making the linkage wrap around the rotor bearing the way Wade has pictured it above. I may order those from Miraphone, but all in good time. In the meantime, I ordered some tight-fitting, narrow-pattern stainless steel washers from McMaster, along with tight-fitting plastic washers. By tight-fitting, I mean washers with inside diameters of 0.12", really designed for the standard looser fit on #4 wire but just big enough to fit over 3mm rod.
Here are the washers--the ones Joe could source locally to him at short notice are at the bottom, and the plastic damping washer is nearly outside the field of view. It's too big, and slid down over the ball too far when tightened too much.
Instead of the bits of tubing, I stacked washers under the ball end and used the plastic washer under the screw head. The plastic washer has a larger outside diameter, so the ball end will bump it before hitting the steel washers under the ball when the linkage wiggles side to side. I could crank down on the screw into the threaded bottom section of the stop arm without binding, and didn't need the nylock screw. I have some 1/8" stainless steel tubing I'll eventually cut into sections to cover the threads across the clevis gap.
Another approach would be to ream out the hold in the upper flange of the stop arm for that tubing, and use a longer piece of the tubing to extend from the lower (threaded) flange to the base of the ball, instead of the stack of washers. If the top flange is reamed for an interference fit and the tubing pressed into it, it will be a permanent construction. Even better would be to use a solid rod and then drill and tap a hole for the screw.
Another issue was that the fourth valve had been replaced at some point in the pre-bloke history of the instrument, but the replacement wasn't machined correctly to fit the thrust surfaces in the old casing. The bearing adjustment screw in the rear cap was used previously to take up the resulting 0.7mm of slack, but we all agree that is a temporary solution at best. Machining down the inside rim of the rear bearing plate might have taken up the slack (and there was already some machining done there) but the rotor would be misaligned--too close to the front of the casing. I blued up the valve and determined that it was still (barely) riding on the bearing thrust surface and not the outside of the valve, but based on arange of measurements using precision measurement tools that I'm always eager to play with, the rotor needed to be positioned further to the rear.
The proper fix, as Joe suggested to me, is to ask Miraphone to machine a new valve using one of the other valves as a model. But I'm impatient and sought an easier fix that didn't require shipping to and from Germany. Again from McMaster, I acquired a stock of brass shim washers in various thickness ranging from 0.1mm to 0.5mm, with a 6mm inside diameter. This was slightly too small to fit over the rotor shaft, and I knew I would have to ream them a bit to fit.
In the end, a single 0.5mm washer did the trick, taking up the fore-aft play in the valve. It did move the stem out of the front bearing by that amount, which meant the tapered bearing didn't fit quite as tightly. I'll swage down the bearing shell a bit to suck up that gap.
This is a low-grade fix, but it works, at least for now.
Joe purposely used hard bumpers on the return to expose any rattling issues, but I'll probably replace those with softer bumpers in the fullness of time.
Rick "fun with depth micrometers" Denney
). I sent Miraphone measurements (rather than risking another rotor body in the mail). They made a complete new rotor body (might have even been rotor #1, which is sort-of an important one...I honestly can't remember which one...it was either #1 or #4) from measurements. I had to final fit it into the casing (at first, it wouldn't drop all the way in), and get it spinnin' good enough for someone to actually USE. 