The Great Kurath Re-Tubing

[the elephant]

So the 1 1/2" x 12" x 1/8" nickel silver bar I received from Jantz this last time pretty much ensures I will not buy from them again unless desperate. It came with some sort of hardened, yellow gunk on it (possibly burnt motor oil?) and every face — all six of them — had the look and texture/feel of an old LP record. It took me all afternoon to sand and file the two major faces and the four edges down to being square enough to use and smooth enough to attempt to buff.

I stumbled on a way to speed the smooth the major faces. I cut off the hunk I need right now and used the remaining length like a whetstone. I sanded and filed everything on the hunk until I had things looking a lot less bad (but still pretty bad) and then I decided to try lapping them together.

It worked very well. I quickly ground the faces until most of the scratches and grooves were gone. This made buffing it to a usable appearance pretty easy. It is not ready for prime time, yet, but that will come after the holes have been drilled and tapped, and everything fits together the way I want. Then I can use more pressure and even some rouge at the end. Right now it is heavily swirled as I only used the Tripoli compound and not much of that.

The end is a piece with nice edges and flat faces that is dimensionally pretty correct and flat.

This was a simple task, but a huge consumer of my time, so once I had it rough buffed I packed things up for the day.

This was the surface and the color *after* I spent time rubbing it down with mineral spirits to melt off whatever this crap was. The edges were all beveled inwards so that the bar is 2mm shorter and more narrow on one face versus the other one.


After several attempts, I discovered that some powdered "Barkeepers Friend" took off the coating very quickly. This is after about 45 minutes of sanding and filing the flat faces.


Five minutes on the buffer with Tripoli cutting compound…


After being degreased and wiped down…


This is how the lever rack will be mounted to this plate. It will get the spring ends out beyond the slide where they need to be, but where no mounting point exists. This plate solves that. It will replace the detachable brace that has been here, holding the French horn levers. This will work much better, I think.


The PITA edges came out much better and faster this time.


I am getting much better at Dremeling these edges so that they look nice.


I am also getting much better at filing the long edges flat and smooth.

[prairieboy1]

Beautiful work as always. That horn will be a jewel when it is done!

[the elephant]

I cut out the hunks of that nickel silver bar needed to make my two huge "tabs" that pull double duty as brace feet and mounting plates for the lever plate. I also decided to replace the French horn bracket for the 5th thumb lever as I want it to have a wider tuba spring. (I cannot stand weak springs.) So I made a saddle that matches the 5th/6th saddle (paddle rack).

Here are the two lever brackets. Making all those little details line up nicely can be a bit of a challenge, and so it rounding off the tops.


Here is today's new thumb lever bracket with the hinge tube I will use. The hinge rod is still cut way too long and will be adjusted later.


Of course, a lot of this will be skeletonized away, but not enough to make it weak. On the bottom are the tabs to the top bow and the 1st slide, next up is that plate I made yesterday. Then comes the lever assembly.

[York-aholic]

Nice. I think you’ve guilted me into redoing the bracket that holds the thumb lever for my Eb. It’s about time!

While looking at things carefully, I noticed I never soldered one side of the brace that spans the MTS.

[the elephant]

Oops…

[bloke]

Don’t solder that brace, unless you want that main slide to hang up.

[York-aholic]

That’s what I was thinking. It’s slides smoothly now. Why mess it up?

[the elephant]

I am working out my left-hand position.

Thus far, everything has fit into these vague "sort of here" and "sort of there" zones, which is fine when you are sitting around scratching your head. I am now having to cut parts and need much more exact locations and measurements. Some of these parts are complex shapes for me to cut out using a Dremel tool, and one uses a lot of material I can't easily replace right now; I need to nail everything on the first try. I can't afford to experiment as I did with the thumb lever (nightmare that it was).

I am creating a "location" on this horn that is currently a three-dimensional void. I have to locate the exact spot the lever bracket has to be to fit my hand. In order to start doing that I need to nail down exactly where my hand needs to be, then create that location. Once done, I can then put my hand there and figure out the next step.

I just fit and soldered in place my pinky ring, which is a nice Bach trumpet 3rd slide ring. I figured out which of the several thumb rings I was considering for this and then figure out where it needed to be, then make a connection to the tuba. Then I can solder *that* in place.

THEN I can start work on where my levers need to go and how to mount them there. I have partially worked this out, but none of the measurements and locations have been noted yet.

Here is a pic of roughly where the lever will go, the pinky ring in its new home, and a sexy poser shot of how nice these Bach rings are.

From this vantage point, the levers need to rotate counterclockwise.


The thumb ring flange will be where the red semicircle is on the right side of the hoop, with the ring hanging below that point.


I have always loved the shape of the profile of these rings.

[the elephant]

Okay: POSITION OF LEFT HAND: SET!

Now I can start work on getting these levers mounted to the tuba.

[bloke]

You might (??) want to solder a nickel French horn handguard on that brass tube that you’re wrapping your hand around.

[the elephant]

Yesh. It is quite pitted. Many parts of this horn are badly pitted. I need to replace two slide crooks and this hoop as they could start leaking. One of the POs of this horn had super-acidic, sweaty hands, and the lacquer on this horn was poorly mixed and applied.

I was actually going to apply a thick nickel silver guard fashioned like the shoulder plates on some Conn sousaphones that has a radius of about half of an inch to make resting my hand there more comfortable.

Also, I had not planned to reuse that hoop until I used it. Best laid plans…

[the elephant]

So the current difficulty is that my levers have to be mounted in a location that does not yet exist; it is an open void. So locating where things need to go, their shape, screw locations, lever swing clearance, etc. is a huge challenge. The first two photos show what I am talking about. The rest of them show how I designed and built the end that connects to the 1st slide. I am still working out the shape and location of the other end, as well as what chunks of the "Big Plate" can be removed.

Aaaaaaaaand PICS!

"Yeah, something like that…"


"… hanging way tf out in space…"


I need a tab on the 1st slide that will accept the "Big Plate" (which will replace my 1st slide brace and will also be where the levers are mounted). The tab needs to wrap around the slide tube about 50% to ensure it is very rigid while spreading the torque of the levers out as much as possible. In this photo I am using my jeweler's saw to cut out the semicircle where the tab will fit the flange, which is a bit of slide tube that I will cut to shape later. Trust me when I tell you that this was the very definition of tediousness.


The tube fits very nicely, so the tedium paid off.


This end is done. I have to hog out a lot of the middle section of the "Big Plate" and still have to figure out the exact shape of the other end as well as the shape and location of the bell tab.


It won't look half this silly once all the excess material has been removed. I hope.

[York-aholic]

I wish I had half of your patience and attention to the smallest detail! You have some serious tenacity!

[the elephant]

Okay, I had to let that stew for some time until I have a better idea of what needed to happen next. I decided to change course a little bit.

Again.

So the 3mm-thick tabs to the 1st slide and dogleg are not a good idea — they can flex just enough to bind up my 1st slide. I need the tab on that side to be 6mm instead, and the flange brazed to that tab needs to be larger, too.

Also, now that I know exactly where the dogleg end of this assembly needs to go I also now know the exact length needed.

And I did everything wrong again.

As usual for me, I need to build at least part of an assembly so that it will hold together while I figure out the other parts. Usually, I guess close enough to use the initial parts (or can save them with a little reshaping) but sometimes I need more material, so those initial mock-up parts become junk. That was the case with this idea.

Yesterday I decided to relocate the far tab from the dogleg to the bell, as on my other tubas. This change solves several small problems for my hand. Then I more accurately measured the space and cut a new base plate and tabs. I decided to beef the tabs up by using the 6mm stock I used to make the thumb ring base plate.

Jantz sent me some scabby, poorly cut bar stock the last two times I have ordered from them, so they are likely off my list of suppliers. Their bar stock has added many hours of work to this project, and I am finicky enough to do that extra work rather than have it look bad and say, "Well, Jantz sent me crap to work with."

Anyway, the parts I need are now cut and shaped so that I can drill and tap them and mount them to the tuba so that I have a functional brace between the bell and 1st slide, that doubles as a stout mounting location for the levers I made.

Here are two pics and a LONG video. (It is 13:19 in length. Since I make truly crappy videos that is a lot to sit through, but I explain a lot, so please give it a watch…)

Here are some of the parts I made yesterday and then cleaned up today…


The two tabs and the plate will go on the horn sort of like this. This will be both my brace and the location to mount the lever rack.


Here is the video. Thanks very much for watching…

[the elephant]

Tappy-tappy…

[the elephant]

Just a video. Today went pretty well.

And now: supper…

[the elephant]

Someone I am connected to on Facebook (perhaps one of you folks?) bought me a gift anonymously about a week ago. I don't know who it is. I don't know how they got my mailing info and email, but I have only ever shared that with some of you guys. And only a few of you are *also* connected to me on Facebook. Anyway, it arrived today.

The artist told me it was an anonymous gift and would not spill the beans, though she was happy that I like it so much (and to make a sale, no less).

If you sent me this gift: THANK YOU!

I will have it framed at Christmas at a local frame shop. It is beautiful. It will hang in my studio over my desk so that I can look at it whenever I am working.

You can identify yourself to me via PM if you care to do so, but if you prefer your anonymity I promise that I won't poke around and try to "out" you.

(Mrs. elephant loves it, too, by the way.)

[bloke]

If (??) there's a way to white out part of it (so as to not reveal who gave it to you), maybe you could do that and show it to us.

[the elephant]

It would likely out the person. Check your PMs…

[the elephant]

Okay, so after a few days of head scratching I have decided to make this last tab (to the bell) using an assembly fixture that I will make. It will be time consuming and a PITA, but I think nailing the shape and angle of the scooped-out area on the first try will only be possible if I first make something to shape it against and then hold it in place while I braze the flange and tab together.

Now I have to figure out how to build the fixture.



Headed out to the shop now…