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causes of rotors clicking - and misdiagnoses

Postby bloke » Wed Jun 20, 2018 10:41 am

The primary causes of clicking rotary valves (valve noise) are...

- much more than .001" tolerance between the spindle bearings (top/bottom). This causes the rotary valve body to (usually) slam against the upper spindle bearing when quickly rotated (i.e. when the lever is quickly depressed). Miraphone (only) has little screws in the centers of their rotary valve caps which can be used as a "remedy", but the fix is to turn down the back bearing (on a lathe, etc.), so that it is able to be inserted into the casing slightly farther and thus eliminate the vertical end-play. If one-or-more rotors make a clicking noise...AND you are able to grasp the stop-arm and (even ever so slightly) move the rotor body up-and-down, there is an extremely high likelihood that this is part-or-most of the cause of the clicking noise. Also, if "oiling the rotor bearings" (top-and-bottom) eliminates the noise for a few minutes, this is an indication of the vertical rotor tolerances being too generous.

- loose center screws. This is the large-head (typically, dome-head) screw that holds the stop-arm tightly against the rotor stem. Some makers offer extraordinary close tolerances between the rotor stem and the hole in the stop-arm, which defines "very tight center screws" as slightly less critical.

- worn bumpers (cork/rubber/silicone). Often the strike-rod portion of the stop-arm appears to not be hitting the metal cork plate, but - when quickly depressed with more force (during actual playing) - it can be seen to be actually hitting (or nearly hitting) metal. This typically occurs with the "strike" bumper, and almost never with the "release" bumper.

- loose cork plate screws. Actually, this is almost never an issue, but is occasionally, and can certainly cause a clicking noise.

- worn or out-of-adjustment linkage. Some linkage (the older the tuba, the more likely) is adjustable, and some is not. Old Miraphone DVS and old Miraphone nylon grommets melted into S-arms usually are ~not~ responsible for very much valve noise (even though old, and even if a DVS link's nylon screw is not adjusted as it should be), due to these parts being a plastic type of material. However, they can make a very small amount of noise, and age DOES cause these parts to harden and (yes) make more noise than they originally were capable of creating. If there is metallic noise, these links (or other plastic links) are probably only partially (or nearly: not) to blame.

- worn sealed bearing linkage. Whether the cheapest Asian-made or the most expensive European-made, sealed bearing links (a respected brand name being "Minibal") do not last forever. Endless thousands of impacts wears on anything, and it wears on these metal-to-metal sealed-bearings links as well. If they become too noisy (and - when removed - a slight sideways movement can be detected with the roller), the only choice is to replace them. However, not very many of these - usually - are noisy, and it is NEARLY ALWAYS one of the early things (listed above) that is actually causing (the majority of) the noise. The round LOCK NUTS next to these sealed linkages should always be checked on these, as those can easily (particularly with the most hastily-built Asian) work loose, and allow the rotation of the bearing to make noise. In the really "old days", the male threading on the ends of the action rods of the "West Germany"-made tubas was intentionally "not quite right", so that both the link and the nut were very hard to turn (which helped them stay in proper adjustment).

- rocking of sealed bearing links. European-made tubas and some of the better-made Asian tubas feature control springs, which help keep sealed bearing links (again: like "Minibal") from rocking left-and-right and making a clicking nose when they move as far as they can move in either direction. Less expensive Asian-made tubas (typically, with small links) don't feature these guide springs, and a click can occur due to the links rocking back-and-forth. OLD "transitional" European tubas used ONE sealed bearing link on the stop-arm end of their action rods, but continued to use the ancient "T-style" hand-made universal joint on the paddle ends of the action rods...and - thus - no rocking back-and-forth was possible. The necessity for guide springs began when the hand-made "T-style" universal joints were eliminated, and when sealed bearing links were used on both ends of the action rods.

- finger paddles' hinge tubing loose between the saddle stops. Oddly this ALMOST NEVER seems to create any noise, no matter how poorly these fit. The paddle springs seem to keep the paddle assemblies pushed against one side or the other, so clicking is only rarely experienced due to this issue.

- non-valve-related issues. Loose solder joints or surfaces that are supposed to barely miss each other but (often, due to damage) now barely touch can buzz or react sympathetically with valve strokes, and with certain pitches. Sometimes, these issues are misdiagnosed as valve issues.

...if anyone wants to reprint this in the ITEA thing, I'm willing to go back over it and make it more suitable for publication (editing, etc.)...but this really isn't long enough to be any sort of decent "article"... :|
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Re: causes of rotors clicking - and misdiagnoses

Postby Mark Finley » Wed Jun 20, 2018 11:13 am

It's kind of covered by loose center screws, but what about a sloppy fit between the stop arm and the stem? If it's sloppy, you usually can't tighten the screw enough, so I have to wrap the stem in Teflon tape to bulk it up
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Re: causes of rotors clicking - and misdiagnoses

Postby bloke » Wed Jun 20, 2018 11:57 am

Lately, it looks as if B&S (Meinl-Weston) and Meinlschmidt may (??) have gone to a laser-cut stop-arm, because they are all one piece (with the strike cylinder on the side actually being of the same contiguous piece of brass). Those fit extraordinarily well, and - if they are pushed down with enough force - may not even need a center screw. Jupiter fit pretty well also, but are made of *pot metal (as are Jupiter water keys), so - when they break - they must be discarded, because pot metal is not repairable...but other stop-arms (whether older European or even more loosely-fitting Asian - made of brass or nickel silver) are going to click, if the center screw is not tight.
______________________________________________
*https://en.wikipedia.org/wiki/Pot_metal
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Re: causes of rotors clicking - and misdiagnoses

Postby toobagrowl » Wed Jun 20, 2018 8:15 pm

A couple months ago, I worked on an elderly gentleman's tuba. It was a Chinese copy of the B&S 'Sonora' BBb tuba. I believe the man bought the tuba cheap from a now-defunct west coast music store. The only engraving on the tuba was "Infinity" on the bell.
The tuba itself actually played very well; nice deep sound, in tune, good response. But the rotor section was terribly clanky and not as fast & smooth as good German or even Czech rotor sets.
After smoothing out the bell creases, I looked over at the rotor section. Oiling both top & bottom bearings as well as the linkage didn't do a whole lot. I finally noticed some 'slop' or 'play' in the ball-&-socket joints as well as the T-joints near the paddles. Oiled those. I had asked him why he had athletic fiber tape around the top screws that hold the stop arms in place. He told me because they kept coming loose! So I took the top screws off, cleaned off the tape and proceeded to take the stop arms off. There was a LOT of 'slop' between where the stop arms and top rotor stems fit together. You could 'wobble' the parts with your fingers. Very loose tolerances; they were fabricated that way. The tuba was only 4-5 years old. The only thing I could then do was use GREASE on those parts and screw them back together. I also used grease on the ball-&-socket joints as there was a lot of 'slop' there too. All of this improved the linkage........a little :| But you can't really do much when the parts are fabricated with very loose tolerances :idea:

One thing I wanna add to this is that when I am doing rotor maintenance on my own M-W CC, I have to make sure the back bearing PLATES are on just right. This is if I actually removed the entire rotor from the casing.
If not, then there is sometimes clanking or the rotor won't move. I have to tap the back plates in alignment "just right" with a plastic/rubber mallet.
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Re: causes of rotors clicking - and misdiagnoses

Postby Paul Maybery » Wed Jun 20, 2018 11:25 pm

There are several things that I did not see covered here which do make a very real difference with regard to the clicking sound. None of these were obvious and took a lot of investigation to discover.

1. This seems ridiculous but. The neoprene bumpers often get a tear in them from the stop arm continually hitting them. It is hardly noticable particularly with the black neoprene. That little tear causes a click like sound. Replace the bumper. Care when installing the new one not to tear it as you push it into place.

2. Similar to using a torque wrench when tightening the bolts on the head of an automobile engine, a certain amount of torgue is needed with the screws that hold down the crescent shaped plate that holds the bumpers.
Sometimes "just tight" is not tight enough. Same can be the case with any screw in conjunction with the valve.
Care to be taken to use the right sized screwdriver and to monitor the tightness very carefully. Over tight of course can strip the threads.

3. The collar screws on the push rods also work loose from time to time and need to be torqued back.

I have done this on all of my rotary valves and "voila" no clicks. They are disturbingly fast and quiet.
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Re: causes of rotors clicking - and misdiagnoses

Postby bloke » Thu Jun 21, 2018 10:13 am

Paul Maybery wrote:1. This seems ridiculous but. The neoprene bumpers often get a tear in them from the stop arm continually hitting them. It is hardly noticable particularly with the black neoprene. That little tear causes a click like sound. Replace the bumper. Care when installing the new one not to tear it as you push it into place.


original post wrote:- worn bumpers (cork/rubber/silicone). Often the strike-rod portion of the stop-arm appears to not be hitting the metal cork plate, but - when quickly depressed with more force (during actual playing) - it can be seen to be actually hitting (or nearly hitting) metal. This typically occurs with the "strike" bumper, and almost never with the "release" bumper.


Paul Maybery wrote:Similar to using a torque wrench when tightening the bolts on the head of an automobile engine, a certain amount of torgue is needed with the screws that hold down the crescent shaped plate that holds the bumpers.
Sometimes "just tight" is not tight enough. Same can be the case with any screw in conjunction with the valve.
Care to be taken to use the right sized screwdriver and to monitor the tightness very carefully. Over tight of course can strip the threads.


With most European-made tubas, over-tightening (which risks breaking off the heads of these small screws, particularly if they are Czech-brass or Asian-stainless steel, and not nickel silver) is not necessary. However, with some hastily-built Asian tubas, the bottom surfaces of the cork plates are not perfectly flat...so over-tightening could succeed in eliminating a vibration. That having been said, most hastily-built Asian tubas' rotors/linkage are only able to be made to remain quiet for a few minutes at a time, so most of these pursuits are - basically - in vain.

Paul Maybery wrote:3. The collar screws on the push rods also work loose from time to time and need to be torqued back.


original post wrote:The round LOCK NUTS next to these sealed linkages should always be checked on these, as those can easily (particularly with the most hastily-built Asian) work loose, and allow the rotation of the bearing to make noise.
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Re: causes of rotors clicking - and misdiagnoses

Postby Doc » Thu Jun 21, 2018 10:18 am

Thanks for this post. I have noise. I have everything tight, and I assumed it may simply need new bumpers. I'll do more checking. I just wish there was competent service nearby to do the things I can't or shouldn't.
All that, plus $8.00, will get you a venti at Starbucks.
Or in my case, a large can of Folgers.
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Re: causes of rotors clicking - and misdiagnoses

Postby bloke » Thu Jun 21, 2018 10:34 am

Doc wrote:Thanks for this post. I have noise. I have everything tight, and I assumed it may simply need new bumpers. I'll do more checking. I just wish there was competent service nearby to do the things I can't or shouldn't.


Grasp your rotors' stop arms. If the same ones that make noise BARELY can be moved up-and-down, I PROMISE you that is the primary source of your noise.
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Re: causes of rotors clicking - and misdiagnoses

Postby Doc » Thu Jun 21, 2018 10:52 am

I will check.
All that, plus $8.00, will get you a venti at Starbucks.
Or in my case, a large can of Folgers.
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Re: causes of rotors clicking - and misdiagnoses

Postby pjv » Thu Jun 21, 2018 5:05 pm

I have an old 163 Alex (possibly '20's) that I paid $500 for, plays amazingly in tune and has a lovely sound all around. It's been beaten up really bad though (silver solder work on a mouthpipe crack, lots of dents, etc). Being a beat-up 4/4 BBb with an older 42.5cm bell flair (about 16 3/4") and (get this) a nickel-plated red brass tuba means I'm not really gung-ho about restoring it.
The valves are noisy, the bearing plates are loose and one is partially broken-off.

So as a temporary fix I use thicker oil on everything that makes noise and put perinet valve cap felts on the bearing plate so that bottom cap itself pushes the valve into place (reducing the vertical tolerance).

This all works in a pinch and at least makes it possible to hear how the tuba responds.

Who knows, if I ever want a 4/4 tuba I might have Alexander do whatever need to be done. But then I'd want 5 valves. Not an easy task considering the valve entrance and exit is at the typical older style 45 degree angle.
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Re: causes of rotors clicking - and misdiagnoses

Postby bloke » Thu Jun 21, 2018 5:14 pm

pjv wrote:I have an old 163 Alex (possibly '20's) that I paid $500 for, plays amazingly in tune and has a lovely sound all around. It's been beaten up really bad though (silver solder work on a mouthpipe crack, lots of dents, etc). Being a beat-up 4/4 BBb with an older 42.5cm bell flair (about 16 3/4") and (get this) a nickel-plated red brass tuba means I'm not really gung-ho about restoring it.
The valves are noisy, the bearing plates are loose and one is partially broken-off.

So as a temporary fix I use thicker oil on everything that makes noise and put perinet valve cap felts on the bearing plate so that bottom cap itself pushes the valve into place (reducing the vertical tolerance).

This all works in a pinch and at least makes it possible to hear how the tuba responds.

Who knows, if I ever want a 4/4 tuba I might have Alexander do whatever need to be done. But then I'd want 5 valves. Not an easy task considering the valve entrance and exit is at the typical older style 45 degree angle.


With a tuba such as that - if not thin/work-hardened/patched, etc...
...Were someone to REALLY want the valves to be "just so", it's not tons more expensive to get a set of four new Meinlschmidt rotor assemblies (and they can orient the upper #1 and the lower #4 at 45 degree angles - like Alex') and just REPLACE the valves vs. one of those "rebuild" jobs...particularly if the rotors/casings are REALLY bad. Meinlschmidt can supply rotors in (at least) every 1/2mm size, and slides-and-tubing circuits 1,3,4 can all be adjusted to fit, with Meinlschmidt sending you their own #2 slide bow along with the stacked rotors set.
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Re: causes of rotors clicking - and misdiagnoses

Postby pjv » Fri Jun 22, 2018 4:52 am

Agreed, but until now I haven't found any repairmen I trust to do the work. The tuba is worth it. The nickel plate does make it harder to work on I imagine. Fortunately theres only one deep dent that might be a crack danger.

If I start on it I want it done well and I want it my way, which means a 5th valve. That means a new mouthpipe (what it probably needed anyway).

And if I'm going to do THAT then I REALLY prefer a different bend in the pipe. I absolutely HATE traditional German-style mouthpipes that go up before they enter the valves because of all the build up in condensation which just sits there (or, if I'm lucky, ends up on my shirt). So it'd have to be custom bent. The mpc receiver when then be positioned higher up on the bell but this is a win/win for me. The tuba can then probably rest on the chair (not that this tuba is heavy, quite the opposite), positioning the valves lower down which is nicer for the wrist in my experience.

Blah-blah. So, yeah, I might take it to Alexander. They're unfortunately very conservative but they will have the correct mouthpipe.
Sorry for the long off-topic post.
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Re: causes of rotors clicking - and misdiagnoses

Postby bloke » Fri Jun 22, 2018 8:26 am

It's not difficult to lead solder to nickel plating...It's not like chrome...just fwiw
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