The Great Kurath Re-Tubing

[bloke]

…at which point you might consider repurposing your right hand thumb as a #1 slide trigger activator (if that is beneficial).

[the elephant]

I decided to haul the Kurath along for the trip to Greenville this morning for our two Young Person Concerts. I have to use it tomorrow for three quintet gigs and have not yet tried it in a group; I wanted to make sure what I was hearing was accurate and that the horn was indeed ready for prime time again.

It is.

I played several large chunks of Fantastique Mvt. 5 and about six other pieces this morning and all went well, so quintet tomorrow ought to be fine. I had done the math to make my MTS be out one inch @ 68º F and it is out 7/8" so I'm pretty delighted with that.

So I *had* to drive home after the a.m. set; we have a Pops concert up in Greenville tonight and I did not want to spend all day trapped up there. Of course, that was a terrible waste of 3/8 tank of gas for only an hour of rest time, but my wife will get to come out tonight to see the concert, and I won't have to drive 90 minutes home late tonight through "Cottonlandia" alone. (It is super easy to fall asleep on those lonely roads at night.)

[York-aholic]

Awesome! That's a nice family photo.

[prairieboy1]

That's a terrific picture! Suitable for framing, I think.

[the elephant]

Okay, so I have been scratching the old pate about the 6th lever. I can build it as it is. I can buy another valve that puts the stem where I want it with the ports where I want them, and at the bore sizes needed. I can rig it up in a "git'r'dun" method and use it that way for the rest of the season, and backtrack as needed in the coming summer.

I vote for that last one.

I have had a *massive* burden of playing work added to my schedule for the rest of the season. I can't really work on this to the extent I need until June. So I have decided to rig up a lever that I am not going to like much, but that will allow me to start using my 6th valve and figure out where slides need to be adjusted to once I work out my fingerings.

This will be one of my unused French horn levers placed on the top bow, inside, about the level of the 4th slide "hoop" where my hand naturally strays to when I am not having to use the 1st slide. It is where I really needed to place both levers, as with a rotary 5th and 6th set. (No, I wanted to have them behind the 1st slide because I am such a subject matter expert. Sheesh…)

So — for now — the 5th will remain right-hand thumb-actuated, and the 6th will temporarily be left-hand second-finger-actuated. I *really* want these to be set up like 1st/2nd (in CC) so I will sort this later on down the road.

At least I'll get to use 6th on the Malcolm Arnold 1st Quintet a few times this Spring in a recital series with the MSO quintet.

Anyway, the lever in this spot will allow me to rig up a very easy linkage to the stop arm that I can likely have installed by the end of this weekend.

We'll see about that, but I will work on it as much as I can. Today I made a start on the level and mounting saddle, but it is using crappy, bent-up, old parts. Try as I might, after all this work, even temporary stuff needs to look decent to keep me from going nuts, so I will look into improving what I did today sometime tomorrow afternoon. If I can get the lever made I will install it. Then maybe on Sunday, I can rig up a linkage rod.

The way I want to do things will involve soldering to one of the piston casings and after my recent discovery of how badly they leak I do not want to do *anything* to them right now. So I am stopping all work on that system for now while I decide what I want to do.

Here are the lever and bracket I modified for this. The bracket needs to be about half an inch longer to put the lever where I want it to be, so I need to think about this before I braze a flange to it and solder that to the tuba. You can see the path to the 6th stem is more or less clear, but might require a bend to make it work nicely.

[the elephant]

Okay, so I could not easily/quickly/cheaply make the temporary lever system. I just couldn't. The materials I have to work with proved to be woefully inadequate.

After two hours of dancing around that fact, I took a break and cleaned up my workspace for about an hour.

Then I looked at the actual 6th lever I have been crafting, tossing out, crafting again, and tossing out again. Recently I came up with the keeper version and then I learned that my valves leak badly and I did not want to solder on one of the casings again.

The issue is *always* the same: to create stuff that connects two points in space, first of all, you have to know exactly where the two points are. To determine where the two points are, you need the parts that will go there. To make the parts you need to know the exact locations where you need the connection points to be, yada, yada, yada.

At some point, when faced with one of these situations I eventually grow a pair and take a calculated guess and secure one of the several locations using a part I laid out using the old "eyecrometer".

A "leap of faith" of sorts? Hmm…

So I slowly and painfully worked out the exact shape of the very weird 6th linkage rod, and the location and shape of the lever setup. I now need to make one final bend to the rod, end-drill and tap it, screw in some all-thread, and thread a Minibal to that end.

Then I need to silver braze a connection point onto the lever for the Minibal's tiny Torx screw.

Then I'll be done.

BUT…

The issue is the exact alignment of the weirdly-shaped rod — it must be exact or it won't work well. That means the dang pillow block has to be installed first. I am *still* not wanting to solder on that casing, so tonight I decided to at least define the space by tacking it on using blue Loctite. I will let that cure for a day, and then the bond should be stout enough to not allow the pillow block to fall off while I create the connection points between the lever and rod.

Then I will remove the pillow block and make a much more accurate one and install that. I expect to be able to play this dang tuba on my Friday morning kiddie quintet gigs including the 6th in several specific places. Once that is done I can set up the upper 5th lever and this thing can finally be put to bed.

After all of that tedious work to bend this stainless steel rod to the *exact* shape I need it to be, I discovered that it is still wrong! Below the pillow block, the straight run of the rod needs to be 13 mm longer before it bends.


There is room in the design for this possibility, though. I can lengthen the short arm between the long rod and the valve. The bend in it needs to be more pronounced, anyway, so I think I will sort it this way.


The blue line indicates the direction that the end of the SS rod needs to be bent. On the end of the rod will be a Minibal that connects to the underside of the lever arm. This looks just about perfect to me.

[the elephant]

Okay, frustration is setting in and I now have a hard deadline for this dang tuba to be FINISHED. I have had to knuckle under and change how I was thinking about the 6th lever. It comes down to this one fact: With the tools I have here, using my chosen materials, I cannot accurately make this 6th lever connecting rod as I wish. I can *almost* do it, but "almost" means "can't" in this case, until I can change my circumstances, which aren't likely to improve anytime soon, unfortunately.

My idea was to make an intricate rod that was both lightweight and very rigid despite having a weak "C" shape to it. I have the materials and the tools, but I have to deal with the level of work-hardening that this alloy of stainless has when drilled or tapped, not to mention the physical difficulty of hand-bending this weird shape out of the stuff.

So I am grudgingly moving on to my next idea… an articulated linkage rod.

I HATE articulated linkages. There should e a lever, a rod, and a valve: very few moving parts. Heavily articulated linkages always seem to be a kludge, no matter how prettified they are once on the horn. I don't see a reason for them beyond intellectual laziness — because I have never had to work out a series of issues as with this tuba. (Sorry, but I see a lot of craptacular linkages made by Frankentuba enthusiasts, and they are frequently designed very poorly. And to me, a linkage with multiple hinge points other than at the two ends is a kludge. Now I have to do this, so deciding to install such a device on one of my own horns is something akin to a defeat.

So, now that I am over myself, I am looking at a three-piece system with a seesaw bar connecting the two ends. I *hate* this idea, but it will work and I can make it look pretty nice.

[Here, in a previous iteration of this post, was a long, drawn-out description of exactly what I intend to make, and I realized that NOBODY CARES. Build it, photograph it, and post it here. Move on with life. So I'll be back when this is finished. Thanks for reading this ridiculously long thread.]

I don't know why I aggressively avoided this system for so long. What a huge waste of time, effort, and money on my part. <sigh> At least now I feel like I am on the final stretch of the trail.

[the elephant]

NOTA BENE: The red rod will have to have a few small bends to get it to fit the space behind the valve and to allow the two ends to align with the stop arm and lever. Nothing is ever simple…

[bloke]

I suspect it will be far better than you suspect, in that it's not suspect.

[the elephant]

Once again, due to the wonky layout of the 4th slide, there is no good place to mount the seesaw's bracket. I have to figure this out, too, now. However, once that single thing is sorted I should be good to go.

[bloke]

A "build-out" for that bracket isn't the worst thing in the world - particularly if it results in a really good fulcrum point.

plus...no-or-old lacquer tubas are somewhat liberating, in this regard.

[the elephant]

I have this almost sorted now. I don't even need the 303 stainless steel rod from McMaster-Carr because this can be built using the nickel silver rod and bar stock I have in my shop. This is much simpler to build out, despite being a much more complex design. It will be very quiet when it moves, and very strong, too. I have the seesaw mount figured out and — I may have already made most of what I need for this part.

Time to play "Oh, Happy Day!" on the iPod as I dance around the shop…

[the elephant]

A "build-out" for that bracket isn't the worst thing in the world - particularly if it results in a really good fulcrum point.

I agree. It is very buildable.

… no-or-old lacquer tubas are somewhat liberating…

Since I muck about with my tubas so much this is why I strip them. I very much prefer the look of a tuba with a nice, even patina. Of course, rarely do you see that. Water spots, finger prints, etc. mar that look terribly. I am always trying to polish my horns on the last few days of the symphony season, then them down and let them set out untouched for a few months to allow an even patina to develop, but no matter what, when packing up from some dang steambath outdoor gig in early September that is on the road, I have to haul butt out of there to beat the traffic and save an extra half-hour on the trip home, so I do not wipe down the sweat-streaked tuba and it dries, salt and all, and the finish I was working on is destroyed. Every year, since 1993 this has happened. Only a few times in my career here have I managed to "grow" a good looking patina.

But MAN, OH MAN is it easy to work on them with the candy coating removed. Same with silver. I love it. I wish all my instruments were silver plated. But I would have to swear off of doing stuff to them, which I could never really do.

[bloke]

I like working on this (identified as pre-) PT-2, because the original lacquer is nearly gone, and - when I've soldered stuff, cleaned up those joints, removed dents, and gone over it with an oily cloth and then a couple of dry/clean cloths, I'm d-o-n-e.

The rotors no longer click up-and-down, the linkage is no longer rattling, and all (but minor bell section) dents are gone...so - once I replace the bumpers, stick it all together, check over the little bell dents, and stick on the wild mouthpipe I bent for it, (again - no shinin' up, no touch-up clear-shootin') I'm really to email the owner.

[the elephant]

On today's agenda:

• A minimum of two hours of very slow practice with a metronome
• Removal of, repair to, and reinstallation of the front bumper cover of one of my cars
• Exercise — I have to walk my mile
• Shower, because walking a mile at my size causes me to STINK
• A nice, hot shower to remove said STINK
• Rest, because I will need it after only walking a piddly single mile (I suck)
• Then, after all that, MAYBE I will get to work on the seesaw hinge bracket

Again, I believe I have a bracket already made but need to build a base, one end of which will probably replace an existing brace, and the will rest on the adjacent tube for stability. (You have to have a very solid, rigid attachment point for a spring-loaded fulcrum point to work well.)

It would be something like this, with a flat bar with tapped holes, and the bracket would be removable, so I can work on it or just delete it without having to replace the brace a second time. The bracket itself would screw down to the red bar. It matches the "upstairs" bracket perfectly (but is only for one lever). I even have the hinge rod/nuts and the outer hinge tube finished. Once the base was made and the holes drilled and tapped, I would just need to install the rocker bar to the hinge tube and it would be done.

[bloke]

..

[the elephant]

And of course, the seesaw idea is physically impossible without a lot of disassembly and folderol which I'm unwilling to do.

"That will bring us back to D'OH! D'OH! D'oh. d'oh…"

(And the goofy rod I had given up on…)


This is the most specific, constrained tchotchke I have ever made. It looks so simple once it is completed. It is NOT simple.


This exact shape took forever to get just so.


Here it is with the doohickey and the short arm installed…


The "short arm" (heh, heh, old military slang) has a Minibal on one end, which is actually called a heim joint. The other end has a single-plane hinge. That is what will end up on the other end. Some cleanup work and this ought to look pretty nice!


I have a non-working Minibal installed as a sort of placeholder. It will have a single-plane hinge eventually.


This crusty, old fart has a terrible attitude problem. Stay away from him. (I was welding earlier and I like the cap. Get over it.

[bloke]

I'm glad to see that you're wearing protective clothing.

[the elephant]

[the elephant]

My move from hardware store taps, dies, and drills to high-quality taps, dies, and drills has been worth every penny. The difference in performance is amazing.

Also, I recently discovered (by reading their website) that the "famous" brand of hardware store taps and dies I have always used are made for CHASING threads, no matter what the actual packaging "hype" might say. I have been using this brand to CUT threads for decades. Because this is what I was taught to do. Because this is what the packaging says. Because this is what the salesman told me. Because false advertising is the norm in America in this day and age.

No matter what the packaging says, Hanson-Irwin taps and dies are for thread chasing, and if you break one while CUTTING threads they won't even listen to you on the phone. "You abused or misused the product."

Irwin taps can SUCK IT.

I have finally learned to spend a lot of money on quality up front so I don't have to run to the hardware store over and over to replace snapped taps and don't have to repeatedly spend $$$ on materials that chasing taps destroy when used to cut threads.

Lesson learned.

Why am I saying this right now?

Because there is some sort of design flaw in the shape of the flutes of Irwin's M3x0.5 tap. It snaps at the same location, every time. If you have to tap beyond a certain depth it *will* break. Guaranteed. Even in soft copper. I have used up about two dozen of this specific model number over the last ten years. For the amount of tapping I do, in the usually soft materials I work with, I ought to be on *maybe* my fifth one. Not my twenty-fifth.

This is the only size Irwin tap that does this for me on a regular basis. I have excellent tapping skills, and have been using taps and dies successfully since I was about 12 years old. (That's four decades for those of you filling in the box scores.) Anyway, I finally called them to ask what was up with my technique that would cause this one size to keep snapping off in my workpieces. I was told — very clearly and sort of rudely — that I was cutting threads and that their taps are only rated for chasing threads. I was also informed that hex dies are for chasing threads; only round dies are made for cutting threads.

Seriously?

Whatever, I decided to visit Grainger and discuss this with a human face-to-face. (I know this guy and he is a non-BS-er.) He also told me that Irwin no longer rates their taps for cutting threads and that this was not new. He said sometime after 2015 they quietly made this change. The metal they use nowadays is a bit more brittle, so the very small taps cut just fine, but they snap once you get about halfway up the threads. To cut with them you must only cut no more than 5º per turn, and you must break the chip after *every* turn. If you can see the flutes twisting AT ALL, it is about to snap. And, once you have seen the flutes start to twist the tap is junk;n get rid of it or it will snap off on the next use.

Now I am ordering all my taps and dies from McMaster-Carr. I got some great help on the phone and know which specific series of taps, dies, and drills I need for what I work on. I also had him suggest what I need for working on the mild steel of my vehicles, as well as the nodular cast iron of the Jeep's differentials (which will soon have air lines plumbed for my lockers) and the DOM steel I am welding into a hardcore roll cage. I have to run wires through some of that mess, and I want to weld in some threaded bungs for a few things. Grainger and McMaster-Carr have some very knowledgeable folks if the phone jockeys can figure out how to get you to them.

Do not use Irwin taps to cut threads. I know you used to be able to do so but I guess this is no longer the case.

Last night I drilled and tapped the end hole for the Minibal on the rod I made. I used a good quality carbide bit and it cut like butter. My old Chinese drills broke off in this same alloy stainless rod a few times. Then, if I could manage to get a centered hole at the depth I needed, the Irwin M3x0.5 taps regularly snapped off in the hole. This became so common that I ended up doing these operations first because it was frustrating to make the object and at the very end have it turned into junk due to a snapped tap.

Last night the high-quality drill (specifically made for working in stainless steel) drilled the hole in about 30 seconds without a hiccup. Then the high-quality CUTTING tap's tapered point made it to the bottom of the hole with no issues, and the bottoming tap finished up without a hitch.

tl;dr — Irwin apparently no longer rates their small taps for thread cutting. They are now listed as thread chasers. Never cut threads with a thread-chasing tap. Always use a cutting or tapping oil. I use Tap Magic.