I got my tools from Herman today! Thanks, Herman! This means the rebuild can go ahead. An odd thing: the HP pins on the Titan and the Trieste are way different. One is quite a bit longer than the other. I'll edit this later when I can look at which is which.
That is not uncommon. Originally Voit used a different pin and HP seat but later switched to using USD (same one in Conshelf and RAM) HP seats which uses a different pin length. Later regs or regs that had been serviced would have the USD seat and the correct pin installed. They are NOT interchangeable, you will need a different length pin to use the USD HP seats in one of them. You can measure the depth the pin enters the seat and figure out which is which. The current USD seats are about 0.300 inch deep.
I put the Trieste back together and hooked up to the tank. I watched the IP move up to 200 + psig and the second stage pooted. I backed the adjuster waaaay out, and got the same result. Hmmm. Been here before with one of my Snark IIIs!
I took it apart and put in another gasket under the bonnet (which fixed my Snark) and got the same result! Poot, poot!
So, I put one of the Titans together and tried that one. Same result! WTH? Stacked up some gaskets under the bonnet. Same thing. Both must have HP seat leaks?
Edit: Turns out it was the o-ring around the HP body.
I've been working on the Trieste and the Titan IIs. I got two of them working properly. It was the big o-rings around the HP valve body. One of the Titan IIs is still doing some weird stuff.
My Trieste is back together, all stock, and one of the Titans now sports a new HPR second stage. I considered lots of options, including machining new LP valve bodies. I made a couple, and was not happy with the end result. There is promise, but too much labor and cost is involved, even before chroming! I took an easier path and I am happy with the result. There is still work to be done on the configuration, since the HPR levers don't look to be in the correct position, height-wise. Won't know what to do about that until I figure out boxes!
I am still considering Rob's plastic FX boxes, since I don't want to cut up good useable vintage parts. The DA cans are not quite right with their offset and all, and the tabs are in the wrong place. They need to be filed off. Also, cutting a big hole in a Mistral top just doesn't seem right. I COULD use the Misuba rev1 can since it's FUBAR for reuse as a Mistral, but I just dove it and it's a winner. I'm going to keep that, as-is. Rob's FX cans are pre-cut for the Trieste, so let's see what that's like!
The second Titan is probably going back together as a single hose. I have two second stages, one early, and one late. The late one is a bit funky, but has some air direction going on in the box. The older one doesn't have that, but it's pretty. We'll see.....
I'm having computer problems today, and can't seem to get to my SD card to upload pictures. I will post some as soon as I can get the thing working.
I ordered a couple of lengths of round delrin in 3/4" and 1" so's to practice machining LP bodies. Brass is expensive, and I'm not that experienced with machine-work, so cheaper is better. I can't think of a reason why delrin won't work for the lp body, if I use 2 washers. Putting 1 under, and 1 over the lever will make a perfect wear point. LP air pressure @ 110-135 psig isn't enough to worry about material-wise. Delrin is pretty robust stuff, and easy to machine. I am copying the original Trieste body, NOT the HPR, since that design belongs to Bryan and Luis. I will admit I went to school on them, though.
I also got the FX cans and a single stage USD type diaphragm from Rob today, so I put my HPR equipped Titan together. It works great! So the Trieste and 1 of the Titans are up and running. The delrin body will go into the other Titan II, and maybe I'll try a set of Mistral cans....
The thing not mentioned: I have no idea what I will do about a lever. I'll make my delrin body and try out the Trieste or HPR lever in it to see how it works, but haven't yet thought about how to make one. One step at a time, eh?
I've been working on the LP body. This rough blank is for practice/experimenting.
I made a little bearing for the LP seat holder shaft, but not because of concerns about the delrin. The little brass top hat is designed to get around some machining hassles. Machining a flat bottom hole with a spring retainer boss up inside requires making a special tool. The top hat does provide a good wear surface for the lever and the LP seat though.
My threads are not up to par here. I hurried the cut and didn't use the proper lubricant for plastic, I guess. It does fit, albeit a little loosely. I ordered a Dremel tool holder that fits onto the lathe so I can mill the groove in the top for the lever and one for the LP body retaining screw. The top picture shows the threaded hole where a cap screw holds the body from turning.
You don't need any lube when cutting delrin. I assume you are single point threading on the lathe, a really sharp cutter helps a lot with delrin. From the photos, the major diameter of the piece looks a little small, if so, that will account for the loose fit and the flat tops on the threads.
It is a few thousandths smaller. I started the thread cut with the lathe and finished it with a die. I probably also went too fast without clearing the cuts often enough. The next one will be slightly bigger. One of the things I need to work on is tool making and bit sharpening. Those are skills I haven't perfected yet.
I've been working on the LP body. I have almost completed one that works. There are some issues to deal with, such as the shorter DA LP seat carrier. The Trieste/Titan uses a longer square shaft. I am trying to circumvent the problem of cutting a square hole!
Some tweaking of the body is needed to make the DA seat holder work. Mainly, this has caused the stock spring to be too long, thus increasing the cracking effort. I think a lighter or shorter spring will take care of it. The lever needs adjusting as well.
The lever is the stock Trieste lever. I still haven't figured out how I'll make one, but it will be simpler than the stock one's compound bends at the base. No need for that.