The Great Kurath Re-Tubing

[the elephant]

Had to slap her back together for some gigs over the next few days. to do that required me to make a slightly longer 5th link arm (from the lever to the stop arm) because the angles and distances with the new thumb ring and lever mean the old one will no longer work.

Lots of cleanup work just to get it up to a non-nasty state.

The new thumb ring location is suh-weet!

I'm as happy as a porker in poop!

I'll be getting around to the new LH levers soon. I got pretty badly sidetracked by my thumb lever woes, but it's all good, now.

[prairieboy1]

That is just beautiful work! Well Done!!

[the elephant]

I have sorted my double-handed 5th lever system, finally! I will start work on it tomorrow.

This last week or so I have been replacing all my crappy Chinese chucks with vintage, US-made Jacobs chucks. I spent hours repairing and rebuilding them. I had a 34-02 from the 1960s on my (also 1960s) Dayton bench motor. It is excellent and very concentric. My Chinese chucks all have a lot of runout, which makes accuracy a PITA when I use those tools.

Well, that has been sorted for under $80 but cost me six hours of work with Swiss files and grinding compound because I do not own any straight reamers to debur the bores. So I did it all by eyeball and feel. Now the larger 34-33 (for my drill press) is like new.

If you even care, heh, heh…

My bench motor 34-02 chuck looked like this…


Now it looks like this…


Just look at those beautiful, undamaged, 65-year-old jaws!


I have the fully repaired 34-33 and have installed it on my cheap-a$$ drill press now, too…


Here is the little 7B I will be using to build a lathe-like "tailstock" for the drill press to more accurately (and quickly) end drill round rod. More on this chuck later…


Here is the 34-33 chuck, taken apart. The bores were a mess. Some jamoke nearly FUBARed it, so he sold it to me for a song. It works very nicely now, though. This was taken after I used nearly a whole can of Brakleen to get all the crap off and out of the poor, old thing. Then I tried to buff up the exterior as best I could (using the wrong buffing compound for tool steel). Oh, well. It looks better. It used to be dark brown and black — and very sticky. Eww… (That's automotive valve grinding compound in the jaw teeth. I was about to wash the thing out to remove the buffing dirt.)


Now I can get back to the Kurath, finally…

[the elephant]

A final bit of Chuck Madness 2022…

I rebuilt the little 7B today. It also had some mushrooming of the bores so that the new jaws could not be inserted. I fixed them the same way I fixed up the other two. After a couple of hours of work, I got the new jaws in, but the action of the half-nuts SUCKED. It was rather disappointing. I went back to the old set and now it works perfectly.

Before…


After…


The N/OS parts came in this cool, old box…




Back on topic…

I dug up the parts needed for the 5th lever and worked out the final design on paper. I will make it tomorrow. I spent like two hours drawing out six or seven designs and then tweaking them until I decided to try another, over and over. Then I figured out a more straightforward design that uses the least material and will take the least time. Rather than a "T" universal joint, it will be like the lever's hinge, minus the bracket.

You'll see…

[the elephant]

Okay, I did a LOT of work today, but most of it was putting around with angles and lengths, but I finalized the lever. I am still unsure about one or two angles and exactly how far they need to be located from the lever hinge to give me the arc and travel I need, but I know from experience that I will have to build it by eyeball, in the end, one step at a time, as stuff like this never works out in 3-D as it does on paper.

With that in mind, I selected all the bits needed to construct this, including the "doohickey" that I need to make it all work. It will allow me to attach a modified "T" flex joint that can only move in two planes, unlike Heim joints like Unibal and Minibal. This will prevent slop in the Z rod so it does not slap against the piston casings when the lever moves.

The "doohickey" was a PITA to make. I improved my drill press and vice some, so that helped a lot. But the cutting and shaping of the part itself (from a hunk of that quarter-inch-thick bar I had in a drawer) took forever — HOURS!

So this had better work or I will fling that SOB out into the backyard, heh, heh…

Here is the basic plan…


Here's the little bugger. I have not yet decided whether I hate it or love it.


I am sort of pissed off because my drill index does not have the needed drill for 5.5mm clearance holes. So this one is loose. It will be brazed together, but still, it should fit better. The drill rod and thumb nut are the ones I will be using, but the drill rod has to be cut way down and then threaded to 4-40…


The angle of the doohickey has to be just so for the rod to the valve to not impact the 1st casing OR the leadpipe union.

[the elephant]

<in a very Elmer Fuddish voice>

It's widget season.
Be vewy qwiet.
I'm makin' duh widgets.

It is taking shape. I have been very sick all week and unable to walk, work, or even watch TV. I am getting stuff done, but it is slow going and not of the best quality. Still, I put in three hours tonight.



I did some peening to make tiny, riveted rollers for my two hinges. I will keep one, but the other may have a threaded nut, as in my earlier drawing. I'm not sure that I want this stuff riveted into an "assembly".

This two-hinge thingie is sort of like a T joint on an S arm linkage. But it is partially disassemblable. (Real word…?) Or, again, it may not be. I can't decide where the breakpoint will be to disconnect the long rod from the lever. Anyway — whatever. (Pfffttt…)

If I opt to have it come apart, I have a very nice Olds French horn paddle rack hinge rod of the same OD as what I am using, and it has a rather spiffy-looking "button" on the end. And I like it. so hmm…

The Z rod fits its space quite well, by the way. This contraption I am making will prevent the slop and banging some of you have warned me about.

And here's your Horn Porn, you dirty, tuba-loving weirdos…

Z rod, with riveted hinge rod inserted in the hinge tube and one of the two Swiss-made Unibal links on the end. I will use these on both valves at the stop arms. Any other Heim-type joints will be the smaller Minibal links. You can see that I have to open up one of the two angles just a bit. The shorter end is a bit too acute.


Z rod, with the Olds horn hinge rod with the spiffy button…


Here is my first *sexy af* riveted roller joint for this project. With any luck at all, there will only be the other one I made with this, and NO MORE. The "rivet" is a 2mm (±) length of the same hinge tube. The drill rod peened over nicely. This one will stay riveted, and I still have to make and silver braze the threaded boss to screw the Z rod's hinge pin into. Once that is done I can put all this together.


End of the Z rod. Stainless 304 and nickel silver braze together very nicely.


Clearance at leadpipe/1st slide/1st casing junction: lever in UP position, close to the casing but more than far enough over to not hit.


And lever in DOWN position, where it swings away from the casing as it descends, getting very close to the leadpipe union collar, but it clears just fine. All that measurement paid off!


EVERYTHING FITS! WOOHOO! (Yes, I know. The lever is not installed. The rod is connected to the valve and just hanging there. Sorry.

[York-aholic]

I believe the correct term is

Takeapartable

Get well soon!

[the elephant]

Good morning.

Old routing versus new…

[the elephant]

The linkage is mostly made. Now I have to re-re-re-re-re-re-make the thumb lever so the drop bar can be positioned correctly to use the doohickey and have the Z rod upper-end location dot the i's and cross the t's, and be made from the thicker stainless rod, which the doohickey was drilled to fit. (It has way too large of a home for the nickel silver rod I have.)

I also bent the "upstairs" levers to suit my needs. I think all this is going to work nicely.

First, pics of the new 5th lever system…






This took me weeks to figure out, what with all the weird angles, lengths, depths, etc. I think it came out decently, though.

[the elephant]

Now some pics of the bent up levers and the finger positions both up and down…

My thumb and pinky will be in rings mounted to the 4th slide hoop my hand is resting on.


5th and 6th levers up…


5th and 6th levers down…

[the elephant]

Here are a few randoms of how the 6th linkage *might* be routed and fit with the 5th linkage.

The brass rod is one of a set of mockups, and this one seems like it will be the winner. It has some funky bends to get it through the little window over to the 6th stop arm. Then it turns the corner and goes straight up to the 6th lever, more or less.


The stop arm end is, of course, too long, and it needs a very short arm with a Minibal on each end to allow for the rotation needed to follow the arc path of the stop arm.


The blue is the end of the 5th thumb lever's drop bar, with a short extension over to the side to line up with the upper 5th lever. The green is the 6th linkage. You are looking at the 5th/6th lever mounting bracket, and the two "balls" are where Minibal links will connect to the short arms up to the levers, which will have Minibal links under the platens.

[the elephant]

That's it for tonight. Thanks for surfing over to take a look. I feel a lot better today than I have in the last two weeks. I walked my mile, even. My outdoor cat Samatha waited for me in the neighbor's front yard for the 23 minutes it took me to do the walk. Good girl, Sam! And I'll leave you with her…

Goodnight!

[The Big Ben]

Good kitty!

Fun process to watch. It's something to be proud of!

[York-aholic]

Oh my. All that planning, bending, and attaching makes my brain hurt. I trust you that it will work and work well, but it makes my head spin. You’re a better man that me Sir!

That’s adorable that your cat walks a bit with you but then waits for you to return!

[prairieboy1]

Great work as usual. Your persistence with these projects is tremendous!

[the elephant]

I am very upset about Doug Whitten's passing yesterday. I'm not sure why I am posting this here. I just am. Rest in peace, Doug.

[the elephant]

Today I wanted to knock out all the rest of the piddly crap that nevertheless *must* be done in order to FINISH this nightmarish lever and linkage and move on to the 6th valve.

The many (omg — MANY) versions of the lever I have built* using different hinge locations, thumb ring locations, etc. have taught me a great deal about *this* specific project. I now have a fully dialed-in (that's 100%, kids!) lever for the 5th RH thumb. All lengths and angles are exactly what I want and what the tuba needs. And after all this work I am coming to the conclusion that I might not be able to make this system (two-handed) work with the valves in this layout. I don't know, you know? I have decided this, though: If this wacky thumb lever and its wacky connection to the other lever and the Z rod to the valve do NOT work I will just make this a 4+2 tuba and dispense with the whole RH thumb thing, which is actually a set of training wheels for me because I am afraid to permanently switch over to a horn with the LH unable to move the 1st slide when needed. I have worked all through the 20-21 and 22-22 seasons relearning to play this tuba so that I do not have to move slides, and it is *almost* there for me, so tonight I decided that if this does not work out — — — — 

SCREW IT!

As a 4+2 tuba, it would be MUCH MUCH MUCH MUCH MUCH MUCH MUCH easier to put together. MUCH. (Did I say it would be much easier?) I am doing all this extra work simply because it would be musically easier for me to still have access to the 5th via my right thumb. That's right. I am lazy to the point of doing WEEKS of needless work.

Except that I want this feature. And, truth be told, despite the frustration I have learned a lot and had a pretty good time working out all the mess into a functioning lever system — or so I hope…

The final task is for me to figure out where to "clock" the "doohickey" to allow for the Z rod to function within the "cage" between the 1st casing, 1st knuckle, leadpipe, and the leadpipe's union collar. I will tell you now that it is not ANYWHERE NEAR where I thought that would be.

Oh well, I still think it will work correctly once I have that little guy brazed in place.

As I am wont to say: WE SHALL SEE…

The drop-bar from the lever is now six inches long, where it has always been about half that. This is because to reach the upper lever it needs to be at least two inches over to one side, so a 90º bend at the precise clock location and a final trim to the length should finish this lever system. Oh, except for the bosses I have to make and braze beneath the two upper levers. And the short rod to connect all this crapola together.

IT. NEVER. ENDS.

Here is where I was when I packed it in tonight…

This is the basic lever rod, minus the drop-bar, the platen, and the hinge tube. I had just hogged out the radius on the end to accept the hinge tube.


I had to file that down for about 15 minutes to get it exactly perpendicular to the centerline of the lever rod. It has to make a 90º "T" from all angles.


And it does, now. Nice. It looks to be dead-nuts-on…


Hinge and platen brazed in place. The platen is brass (and from the original thumb lever from Herr Kurath's shop), the hinge tube is nickel silver, and the lever arm is the 303 stainless.


Before I work out exactly where I need the drop-bar to drop from I wanted to check the fit with my hand. And it fits nicely. This is up. Can you guess what position the next photo will show?




Probable "doohickey" clocking. I might change this, but I think this will work. I may superglue it in place to try it for a few minutes. I can get the residue off before I braze it to the drop-bar. Also, I did not have the correct, stinking drill bit for this 5.5 mm stuff, so it is loose-loose-loose. I may opt to dimple the edge of the hole just enough to hold the thing square to the drop-bar. I hope I don't need to do that, but I think I will…


This shows the backside view (horn on bell). You can see how long the drop-bar is, and how it will neatly line up beneath the French horn levers, eventually. If I ever get that far. Ugh…


_______________________
*Including the three I made for the first thumb ring relocation, three for the second location, and three more since the relocation of the pivot point from the 1st slide to the 1st valve casing, I have made nine levers. Nine. Stick that in your pipe and smoke it. I'm DONE! ;-)

[hrender]

Doing things the way you want them done is always worth the effort... even when they don't work out. At the very least, you'll have an entertaining story.

[York-aholic]

I suspect that inside, you’re doing it for the challenge. I say, good on you!

[the elephant]

I spent some time today looking at how the Z rod lines up in its "cage" as I described earlier. I fooled around with the Doohickey/double-hinge assembly, trying to determine how it needed to be clocked on the drop-bar. Then I was able to figure out that the space between the two rods in the Doohickey needed to be 2 mm farther apart that my original guestimate. This will allow the Z rod full motion without contacting anything on the four sides of the cage.

I messed up Doohickey No. 2 (le Deuxhickey?) juuuuuust a little bit. It is purely cosmetic, but it bugs me enough that I *might* opt to make another. (Troishickey? Sorry, I had to…)

I will test fit it tomorrow. I hope that I will be able to braze le Deuxhickey to the lever and be done with it. Due to the difficulty of making one of these things, I think I can convince myself to "unsee" the boo-boo.

Pics…

The complete double-hinge assembly, sitting on the bar stock from which le Deuxhickey will be cut. I have measured, scribed, and center-punched it, and am about to hit it with the Dremel tool. The new one will have a wider span between the holes, and the hole for the drop-bar will move down from .225" to .219" ID.


Here is the new lever with the longer drop-bar (that will get bent over to the upper 5th lever) pressed into the hole drilled through the bar stock. I need the two rods to be very parallel and coplanar, so this is a pretty tight fit to prevent any slop when this is in the brazing fixture, and in this photo, I have lightly lapped the rod to the hole so that it can more easily be slid on and off.


It's a snug fit, to be sure…


Tappy-tappy. It's thread-cutting time!


Oh, man, that 60-year-old Jacobs Chuck I rebuilt and put on my drill press has made my life easier — this came out great on the first shot! My dial indicator says there is a total indicated runout of about .002" which is not too bad for what I paid!


To me, that looks to be about as close to perfect as I am ever going to get without owning machine tools.


Test fitting le Deuxhickey prior to buffing…


le Deuxhickey, meet the Doohickey…


Assembled lever, le Deuxhickey still loose. I'll mess about with this tomorrow and decide where to go from here. And I promise never again to stylize it as "le Doohickey". I was just having a bit of fun.