The Great Kurath Re-Tubing

[the elephant]

THANKS! I keep running into the dang things and I'm sick of using a Phillips head to try and "get by".

[hrender]

De nada. Here's the blog post in case you're curious.

[bloke]

That’s a good article.

With stuck screws (on musical instruments), this can matter, but - otherwise - probably not too much.

More often, screw rods (hinge screws) on woodwinds are those (rust, and/or lubricants - which have dried and become cement) which end up being stuck, and their slots - unfortunately - are not supported by anything other than the diameter of the steel rod.

In carpentry (most all: larger than brass and woodwind screws, and many being over-tightened by intention and design), it has been determined that torque screws are about the only type of fittings that hold up to impact driving (impact driving being not new, but “relatively new” - and quite predominant), as torque-headed construction screws have really taken over.

Due to the constant repeated impacts subjected to rotor links, torque-head screws are taking over in that subset of musical instrument screws.

In the past, nickel silver screws were considered about the best for many of the really tight static applications on brass instruments, because the alloy is strong - yet it stretches a little bit (adding a “spring-tightened” effect), but I’m seeing those disappear and being replaced with stainless steel, which is more rigid, and which sometimes explains why screws tend to work themselves loose more often on more newly-made instruments. Some alloys of stainless steel are so break-resistant that they are fine, but I’m also seeing alloys used that are obviously lower-grade (on obviously lower-grade instruments).

[the elephant]

I am assuming that you mean Torx screws. (I have never heard of "torque-headed" screws. I have only ever heard these generically referred to as "star drive" or "6lobe" when the Torx name is not used. So if I am assuming incorrectly I apologize.)

Like JIS, Torx screws are designed specifically to NOT cam out, whereas Phillips screws are designed TO cam out, so different purposes and applications, and yes, using Phillips heads for impact tools is a stupid thing to do, since they are designed to cam out under too much torque. I have a car here with a TON of JIS screws that I cannot get apart to restore because I do not have the proper drivers, the fasteners are rusted in place and require impact tools to remove them, and Phillips-headed impact bits destroy the JIS screw heads every time, 100% when air tools are used, which is the only way to break free the hundreds of the little buggers that are rusted in place.

My comments were about the damnable JIS screws that Yamaha still on occasion uses, despite the fact that only one or two toolmakers in the whole world still make tools that support this standard. And Yamaha "stainless" screws are very soft. Stainless hardware is usually about a Grade 3 in hardness. (Mild steel fasteners are usually Grade 5 and suspension hardware is usually upgraded to Grade 8.). Stainless hardware, then, is something you can fairly easily crush with a BFH, so a Philips head screwdriver in a soft JIS slot is guaranteed to tear up the screw head. If you have to remove it more than once or twice with the wrong tool you can ruin the screw and make it very time-consuming to remove. (And then you have to replace it.)

JIS is superior to Phillips when you don't want the tool to cam out, slip, and scratch the surface of the horn, because the tool has a much more powerful grip inside of the fastener head.

I really like JIS, but I also hate JIS because I cannot locate the correctly-sized drivers for what I need. So when I have to have hardware that will not cam out I try to use Torx, but when I need to get some torque and need something I can get at the local hardware store I use Allen hardware, which is inexpensive and easy to locate, even for very nice stuff.

[bloke]

yep - Torx

I guess I was relating their copyrighted name with the torque that they are able to receive and deliver.

It scares me to death to tighten down stainless steel (plain slotted) center screws onto stop arms on Chinese rotary tubas, because the fit is usually sloppy (much like the intentionally-sloppy/damage-avoiding fit of the delicate skeletonized DVS stop arms to Miraphone rotors, back in the day), but those stainless steel center screws (being low-grade stainless steel and slimline-headed – combined with me trying to tighten them as much as I can so the stop arms don’t rattle) is asking them to break.

I’m sure they are less trouble for Chinese manufacturers and German manufacturers - whether the stainless steel is high-grade or low-grade - because they don’t tarnish, and - thus - don’t require being polished and lacquered.

nearly off topic sidebar:
It costs me quite a bit more money (and time) to build outbuildings, fences, decks using all Torx screws - rather than a nail gun, but what’s really nice is that those things stay put together - and those screws - well-embedded - usually don’t even allow the (inferior to that made prior to 2004) treated lumber to warp very much.

[the elephant]

Stainless steel is such a weak group of alloys for fasteners. In my cars, I have tried to remove all my stainless hardware when it has to be "tight" (as with a specified torque value). I only use that junk for things where one grunt is all you need to tighten or loosen them. I have switched to black oxide or galvanized Grade 5 hardware when anything reliable needs to be installed, especially on my "real" Jeep that gets the snot beat out of it. Stainless is fine for interior plastics and door cards and such. And yes, it looks nicer.

On my tubas, after purchase, I have discovered stainless hardware that I have replaced over time with nickel silver because I don't need it to look like stainless, and I don't mind running the polishing cloth over them if I am also bothering to do that to whatever they are attached to. I don't like the look of stainless on raw brass that is flat and brown. I would rather have the NS hardware that sort of matches what it is in.

The exception here would be the Torx screws in the linkages of my 186 tubas because finding them in another material than what is supplied by the maker is almost impossible. And, being so small, and in an area where I do not want a lot of scratches, I greatly prefer Torx. (When you buy the screws for these from Allied or from Ed S. they source Phillips heads screws that are not the same length as the originals installed by Miraphone, which uses the stuff supplied to them by Martin Seibold, the maker. You can get them with or without the screws, and it is easier and probably cheaper for Miraphone to buy the screws he supplies, whereas in the US that bumps the price up a lot. I bet Allied just picks up bulk bags of them at a local bolt and screw store for pennies each. Anyway, they do not match the Miraphone-installed screws at all, and they make it easy to screw up and scratch a horn if you are working quickly. The Torx screws are much better and are all the correct length, so I only buy links with the screws and the very effective neoprene-impregnated nickel silencer discs as a set of parts. (I use those gimmicky, little Delrin or nylon gaskets that Tuba Exchange and Jin Bao use on these Minibal (or copies of Minibal or Unibal) Heim joints, but I don't like them because they do not work as well and they are not provided for free. If I have to spend anything at all I will drop the little bit needed for those metal silencers any day of the week.

[the elephant]

@bloke

Joe, since you are in here reading my earlier post, I have plans to replace my links on my factory CC 186 with old S arms using the traditional T hinge at the lever end. These are just, plain better than anything else I personally have ever seen.

However, I hate the valve end of this system, and I really like the Minibals I have right now, so I want to machine the valve ends to accept threads so I can install Minibal Heim joints from the S arm to the stop arm. If I can make it *look* like something other than some homemade junk I will likely do this. If I can't make the curved S arm look like a Minibal is supposed to be on that end then I may just build the T hinges and braze them to the ends of my current smooth link arms.

I see the S arm with its T hinge as the superior lever end and the Minibal as the superior valve end. Also, I want to make the hinge mechanism removable via knurled thumb screws, like on the paddle lever rod.

Are you laughing yet?

Yeah, I thought you might be. HAHAHA!!!

[bloke]

no laughing, but you’ve now got me thinking on how to accomplish it and make it look “pretty”…(??)

That having been said, those $1 melt-in-place and file/drill-out-to-fit nylon bushings worked remarkably well, and noise - actually caused by rotor body bearing wear - was always misattributed to them…

===============
Were I determined to fit a Minibal link to the tip of an S-arm, I can’t imagine much other choice than chopping the end of it off, and brazing on a short piece of nickel silver rod with a 3 mm thread within it…(??)
We don’t usually order them this way, but I seem to recall that they manufacture some of those links with male threads, rather than female…

… and yes, male threads could be brazed on to the chopped-off ends of S-arms, but I just don’t think it would be as strong as what I outlined in the previous paragraph.

[the elephant]

It is an interesting problem to ponder as I ingest heated bean juice at 6:30 a.m.

Also, I have been gigging a lot again for the first time since March of 2020, so I have been tacet a lot more than in the recent past. While trapped on stage with these tubas with nothing else to do, I stare at them and work out things that I would like to eventually do, how I will do the work and what parts might be needed. (Seriously, no joke. I do this at every gig; it is how I pass the time without fidgeting in front of the audience.)

I have worked out the next set of things I want to do to this tuba, and it will involve a complete teardown — again.

More in the next post…

[the elephant]

I have a dislike for the look of Herr Kurath's round-footed braces. They have the same look as a lot of mid-century, mass-produced American furniture that I dislike so much. (If you know much about furniture design trends you might get what I am talking about, here. If not, don't worry about it. Just know that I don't like the look of these braces; to me, they look cheesy.)

The look of the overly-long, plain sockets with the short run of the overly-thin rod between them is something that I do not want on my horns. It is a design cue that is a big part of a lot of furniture I have thrown out over the years. Blech…

Further, ALL of the braces on this tuba are way, too soft. The flanges are thinner than anything I have ever seen, and being yellow brass, they are very easy to bend. All of the rod stock used with these doofy brace feet is too thin for the forces they are supposed to counteract, and all of them are BENT in the middle because of this. ALL. OF. THEM.

The lengths of the sockets are not uniform, even on a single brace. It looks as though he made these from scratch while eating his lunch and listening to the news and talking on the phone at the same time, i.e. while distracted. I have two long braces that are next to each other, and all four feet have sockets that do not match up. They look like crap. Remember that before this design morphed into the Willson 3200 FA-5 it was a sort of boutique tuba and very expensive, so this sort of sloppiness is inexcusable to me. A lot of internal joint fitting is likewise very poorly done.

Anyway, I intend to keep the round feet, but use consistent and higher quality brace parts. This will be time-consuming, so it won't likely happen in one project.

It also needs a new rotary valve as this one leaks like a sieve. Once I discovered this and "fixed" it with overly-thick lube a lot of things improved. I am currently using Miraphone slide tubing, so I am buying the correctly-sized valve to match what I am currently using, which is a 20.35 mm valve that falls right between the 186 valve (@ 19.54 mm) and the big 191 valve (@ 21.2 mm) that I have on my Holton right now.

To make this work and fit correctly, I have a short cut-off of leadpipe from Allied that will replace the short, tapered piece between 4th and 5th that will require no adjustment at all. The inner/outer slide legs are already the correct size. I have two slide crooks and a couple of 90º bits on order from horns that use this valve.

I have decided how I want that 5th circuit to be shaped, too, and it will improve ergonomics a little. Right now it pokes me in the abdomen, which hurts after a few hours. Herr Kurath rerouted the 4th and 5th circuits several times over the life of this tuba as well as the 3200 FA-5. Photos of these horns over the years show that he fussed over this many times. The final version before his son came on the scene and altered it into the current XL seems to make the most sense to me, so that I what I will likely try to duplicate. It is how I routed my 5th on the Holton, so I know it plays well.

The 4th slide circuit is a mess on this tuba. Both of his Kurath-branded tubas (he just had the one CC and the one F) have this distinctive 4th wrap whereby both slides point down, one in front where the lower 4th would normally be, and one in back by the bell ferrule. The "hoop" of tubing that connects them is the only place to rest your wrist on this tuba, and it is probably 2.5 or 3 inches too low to be comfortable. (On the CC it was so bad, the horn was so difficult to hold, that he dumped it and did a complete redesign to get his later Willson 3050 CC. The Kurath CC was a really great tuba, but no human being could hold it without some effort and compromise to comfort. It was a huge bear of a horn. I guess he could not reconcile these issues with the wonderful bell and bugle wrap had designed, so he tossed it completely. [That bell and the outer branches became the DEG Super Magnum Bore GG contrabass bugle for a few years. If you ever want a great CC Frankentuba project, get one of these old horns and harvest the bell, bottom, and top bows. If you can locate one of the very rare 4-valved ones then you have a great piston set, too.]

His Willson 3400 Eb has a more normal 4th slide routing, so I don't see anything wrong with dumping this one. However, due to the space available and the length of the 4th circuit, I may have to add a wrist rest tube, which I don't like doing. I think the BMB F has one of these. I have seen other horns with them. They all look weird and out of place to me, but I *must* have a rest for my left wrist. This is how I hold the tuba while playing. I do not hold it with my arms but with my left wrist, with the left hand manipulating the 1st slide.

Finally, I need to tilt the valve section a little bit. It was assembled with it at a funny angle, and altering that is pretty easy to do, but it will alter the angle of the connection to the leadpipe. I already screwed up the leadipe with a midcourse change in design when I made the valve set removable a few years ago. I decided at that time that I would get a new leadpipe at some point in the future. When I reset the valves the change to the big end of the pipe will be small enough that I can make what I have work with some lead-bending. But I still want a new one because of my earlier mistake, so that may also be on the To-Do List.

Like with the Holton 345, the more I do to this tuba the more stuff I find that was done carelessly or too quickly. Once it has been gone over completely I will be happy. I had never intended to take this horn apart to this level. But I had never intended to do that to my 186 or 345, either, and I have been very pleased with those two horns since all that work. So far, this horn has likewise responded favorably to all my work. Unlike the Holton and the 186, I use this tuba all the time, so I can't tear it down and fix everything all in one go. I can only work on this horn when my playing schedule permits.

[bloke]

In the past, I bought nickel silver sheet discs from a place sold them in several sizes. I used a couple on that Kaiser baritone of mine, when I was adding a valve and moving so many things around on it.
nickel silver sheet metal disks in various diameters (would probably recommend 24 gauge)...
https://boppermetalsupply.com/products/ ... 4162232420


I’m thinking that you could take some broken/cracked King, Olds, and Reynolds 1/4” i.d. socket flanges, cut the sockets off of them, clean up the bottoms of the sockets on your grinder, and braze them on to some of those discs. The fact that you would have brass against nickel silver would look fancy, much like some of the old West German Melton braces.
(In my experience, it’s easier to bend the disks - to fit the surfaces on to which they will be soldered - before you braze anything onto them.)

If you don’t have a bunch of these old busted braces (since you don’t do a lot of school repairs), you could post on the main forum and ask some of us to mail sockets to you. If we take them off of the flanges first, we can put several in an envelope and just pay the price of a fat letter - to mail them to you. (Could you make these on a lathe? Of course. Would recycling sockets - from busted braces - be a lot easier than that? Yes, it would.)

If you prefer to come closer to that slightly smaller Kurath brace rod diameter, you could buy Jupiter socket-flange braces from Nashville, and cut those apart.

Also, it's my understand (have never done it) that stainless steel can be soldered with plain-ol' tin-lead solder and flux. It's easier to find stainless steel round bar stock (in various smaller sizes) than nickel silver, the color is very difficult to discern, and the density/weight are very close. Stainless steel calls for different polishing compounds, etc., so here are a couple of handy S.A.E. sizes that are PRE-polished to a mirror finish:

ss rod sae polished.png (31.31 KiB) Viewed 1074 times

Otherwise, here are some possibly-useful (un-polished) metric sizes:

ss rod.png (18.73 KiB) Viewed 1075 times

[the elephant]

Ha! I totally rewrote that as you were commenting on it.

The only thing I am having difficulty locating is 5.5 mm (7/32") NS solid round rod stock. NO ONE has it. Brass, copper, and aluminum? Sure! But NS? No dice.

I have some inquiries in, but I will likely have to try the SS as I am pretty sure you *can* find 5.5 mm in that material. I knew at some cranial level that SS can be soft soldered, but have never done it, so I never considered using it on a horn. I will look into that.

The Miraphone adjustable braces are something I have never come across, so I had not considered using them before. However, a quick scan of pics on their website shows them to be very common and available in many sizes, so that is probably what I will go with. I bet they even have some 5.5 mm NS rod somewhere in that building that I could buy…

[the elephant]

Okay. thanks for the idea.

I just ordered four 6" lengths of 7/32" 303 stainless round rod. I will experiment with the Johnson's liquid flux I use to see how it bonds to brass. Johnson's makes several stainless fluxes that are more aggressive. If what I have does not work I'll give that a try next.

I am curious to see how this looks next to nickel silver. I know it will be a darker color, but 303 ought not look too dark, certainly not as dark as chrome. I think it might work well.

The Edwards braces I like utilize a 7/32" rod, but they do not have it in NS. This tuba specifically had badly bent brace rods because they were too thin for the lengths he used. Since the lengths have not changed and these are now removable, I want them to be extra beefy. Yellow brass left a bad taste in my mouth (*ahem* figuratively) and I wanted to use thicker rods made from NS to match what I did elsewhere on the horn. I hope this SS is a good option. I'll post about it here once I know something.

I think 303 will work well for this, but 304 has more sulfur in it, and apparently, that makes soldering it more difficult. I have never soft soldered steels before, only brazed, so this will be new territory.

If 303 is what is used in most mouthpieces it ought to not rust (like cheap, brushed SS sinks and such do) but should look nice for many years at a stretch, once they have been soldered and properly cleaned up. This may become a good (and less expensive) solution for me for longer braces.

Again, I'll post up what I think about 303 stainless brace posts once I know something.

[bloke]

I have NO idea why-nor-when-the-hell I bought these three-piece Willson brace sets, but here they were - in a sack, RIGHT IN MY FRIGGIN' WAY - when I was just about to straighten a (brand-new, of course ) Bach 50 bass trombone inside slide tube (that finally arrived, along with other parts for the same instrument).

It was actually sitting on the corner of the lathe table, up against the tail-stock (which I needed to move OUT, as inside slide tubes are longer).

They're brass - so you probably don't want them (??), but - if you do the research - and ask Dave Surber (at Getzen...so I've just about spelled out his email address, here) how much they would charge you for these sets, you can buy as many of these from me (up to "however many there are, here") as you need/want/whatever for 25% less.
(You could try asking Willi, Jr., but - if he doesn't blow you off completely - he'll almost certainly refer you back to Dave.)




OK...I finally remembered why I bought them, but that project was sold off before it was ever even begun.

[the elephant]

Those are a LOT more professionally made than the hardware store-looking ones on his earlier Kurath. Again, I suspect my horn was an earlier prototype. The Kuraths I have seen used these same braces. Mine is just randomly OD/ID/length bits of brass tubing. Only a few match each other. Mostly the tube is very thick and the center rod is very thin. The discs are of varying sizes and thicknesses and look to have been hand-stamped with some sort of automotive stamping kit. The tubes were brazed on neatly enough, but several did not get enough filler, so the sockets/bits of tubing snapped free of the base discs. The lengths of each pair of socket/tubing match, but braces right next to each other have tubing sockets that are of differing lengths. Many of the flange discs are brazed to the tube sockets slightly off-center.

It is irritating to look at when working.

I appreciate the offer but I probably would never use those braces. If I decide I want them I'll inquire as to the price and how many you have. One question, though: are these all the same diameter flanges, same socket length, and rod OD, or are these different sizes, as though for specific locations? I am interested but do not need them. Thanks for the info, though.

[bloke]

They appear to all be the same, as is the same part number is on the outsides of the packages of every set.
I haven't examined them particularly closely, but it appears that (per each set) one flange is bent smaller, and one is bent more open - though - as they are brass - that would be very simple to change. The flange disks are both the same diameter (per pkg.) Obviously, mixing/matching could result in matched-bend flange sizes (if desired...??) on both ends of a brace assembly. (Again, bending either one wider or tighter would be child's play.)

At one time, I had a totally-unbraced/"floppy" (yet new) E-flat piston Kurath (well...whoever actually made them) valveset, was considering it for my cimbasso (after cutting everything to F), decided that I wanted a slightly more resistance, and went with the Meinlschmidt-made rotary stuff that you're seen on my finished instrument.

Bartering - for firewood chores at blokeplace - IS on the table.

[the elephant]

Thumb Ring and 5th Lever Fitting Blather

Okay, so I have been sick after my overnight trip to San Antonio and Austin. I have not done *anything* on this project for days.

Tonight I tried to figure out why I am so unhappy with the position of the thumb lever, which is pretty much where it was when I bought the horn. The thumb ring, however, was a big, beautiful Cerveny-looking hunk of nickel silver that I hated to remove, but it was not adjustable and it was in a PAINFUL location. And while some here do not think that hand and wrist ergonomics are important, they have not played for enough hours in a day for enough days to see this. IT MATTERS! (I'm calling YOU out, Melton! The location you chose solely for reasons of money rather than player comfort for the thumb levers on your tubas that use the Big Valve piston set. Shame on you, Gerhard!)

For most people, operating a heavy thumb lever with the thumb tucked over the palm is just no bueno.

I spent a good bit of time tonight working out what exactly it is that I like so much about the thumb position of my Holton and hate so much about the same with this tuba.

Here are two photos that will compare where my thumb lives on both horns. This was difficult because the Holton has the far more comfortable 45º valve angle while the Kurath has vertical valves. So I rotated the Holton photo to line up more or less with the Kurath valves and then compared them.

Wow. Just wow. No wonder my hand aches so much when I play the F for more than a few hours in a single day…



This will require some thought to come up with a way to mount my thumb ring where my hand wants it to be.

[the elephant]

The dogleg lies directly below where the thumb ring *ought* to be. Perhaps a very long post for the thumb ring? That would take a heavy "deadener" off of the 1st slide loop. Not that that would actually *change* anything.

Just whistling in the dark, here, folks. I got nothin'…

[the elephant]

Well, I suppose I could just do what Herr Kurath did when he released this horn as the Willson 3200 FA-5. I would try to purchase one of these, but I would have to cut off the bracket space at the bottom as I do not want my lever hinged down there and on that plane. Also, it is not quite long enough, vertically. I can make something like this, I guess.

D'OH!

"Mischief managed."

[bloke]

A thumb ring can always be placed wherever anyone wants it, and tilt at whatever angle anyone wants it to tilt. The questions are always how much trouble it is to put it there, and how stupid all the junk will look that holds it there.

I don’t know if you noticed, but I used a rotary lever carriage bracket to mount the adjustable thumb ring on my compact Holton. I got the idea from Yamaha, as they do the same thing to mount the thumb ring on their contra.

Hey… The intelligentsia is/are always claiming that - when they take the fifth valves off their instruments - they respond better… So why don’t you just follow those platitudes/groupthink (you know: “The Science”), and do that?

(I hope you feel better, and I hope this made you laugh a little bit.)