When I contacted for the boiler, the boiler maker said the throttle was very difficult to install and volunteered to install the throttle for an additional $250. That of course was a challenge, and since the the parts cost about $10, I decided to do it myself. One of the thoughts was that if I did it myself I would know how to get at it for any necessary maintenance. Turns out that it takes an hour or two to make the parts and a few minutes to install them if one doesn't do anything stupid. Of course, I did something stupid, so it took a bit longer.
The throttle is a common 1/4" pipe brass ball valve (brass body/stainless steel ball) located in the steam dome. The valve is controlled by a rod that connects between a lever on the valve and the throttle lever on the boiler backhead.
Dumb! Dumb! Dumb! At this point I felt pretty proud; installing the throttle is no big deal. I then tried to install the two screws ---- very hard to turn and could only get them in a turn or two. Darn! Figured the holes on the throttle assembly weren't the same spacing as in the support causing the screws to bind. The holes in the assembly were slightly oversized, but maybe not enough. No problem, take it back out. The cotter pin was pulled using a stiff wire with a hook on the end. The tip of a screw driver was then used to push the rod out of the lever. When doing this I thought that maybe the front of the rod should be secured so that it doesn't fall into the boiler. Less than a microsecond later the rod popped of the lever and slid into the bottom of the boiler. GRRRRRRR!
The lever is stainless so it could have been left in the boiler. However there is the pride factor. Getting it out looked impossible ---- the boiler is crossed with the tubes and there is a flat stay plate beside the hole in the backhead. And, the only way to get it out is through that hole in the backhead.
Turns out that it came out fairly easily --- this time I thought before acting. Turned the boiler upside down and found that the rod fell to the bottom --- on top the steam dome hole. I was able to loop a wire over the rod. Then turned the boiler right side and pushed the rod as far as it would go to the front --- the back end of the rod was at the rear side of the dome opening. I then slipped a length of 3/8" OD copper tubing into the gland hole in the backhead and then pushed it into the boiler and worked it over the end of the rod. The only problem with this was that the the tubing was restricted by the stay plates. However, a couple minutes later the end of the rod was in the tube. The tube was then pushed to the front of the boiler forcing the entire straight part of the rod in the tube. The tube was then withdrawn with the the rod inside.
I had mixed emotions about about including this whole episode --- however it might be useful as encouragement to other mechanically challenged steamers.
Those screw holes: Before enlarging the screw holes in the throttle assembly, screws were tried in the threaded holes in the throttle support. They would only go in a turn or two. The inside of the boiler is pretty rusted. The boiler was soaked in pickling solution before the silver soldering. This left a clear surface that oxidizes quickly ---- and the boiler had set around for months after it was made. So, it was likely rust in the threads ---- all the was needed was to run a tap through the holes. Fat chance --- no way could I get a tap in the steam dome. Then remembered that those black machine screws are really hard. Ground a couple tapered flats near the end of a screw making a poor-man's tap. A large T- handle hex wrench and and a few drops of tapping fluid cleaned the threads. Actually did it twice with two different screws to get them really clean.