Rotor rubbing/friction sound

[valvehalla]

Hello!

I have an old'ish B&S F tuba (GDR, around 87) that has a strange rubbing noise on the 5th valve.

I've visited 2 techs so far, and neither of them were very concerned about it as the rotor is free-moving, fast and doesn't bind at all.

A few observations with the techs:
1. Upon disassembly, we could not see hard / stuck-on grime that could explain the sound. We did however still thoroughly wipe the casing interior and rotor/bearing, to no effect.
2. The casing interior has patches of silver plating (should it be plated!?)
3. We could not feel vertical nor horizontal play in the valve while still assembled

I created an album that has a few videos and pictures: https://photos.app.goo.gl/kusFQS7xtkhLqM5RA

One tech did suggest lapping the valve slightly, but I'm concerned about ending up making a worse situation (I'd rather have a slightly noisy valve than a leaky one!)

In any case, I understand it's probably difficult (impossible?) to troubleshoot this over a forum, but I figured if anyone has had a similar situation or any feedback/suggestions, it would be much appreciated.

[bloke]

If you can turn the rotor and it doesn't make the sound by itself - but it makes the sound with a linkage hooked up, the noise is probably in the linkage. Have you looked to see if the spring is squeaking against its saddle?

I guess you've tried moving the linkage by itself without it being hooked to the rotor.

Videos - even with audio - really don't tell a very good story with things like this, though I appreciate your efforts to communicate with us.

That's not the latest technology linkage there, I'm sure you're aware of that.

I'm sympathetic with you.
Even the cheapest crap Jinbao rotary tubas (models that at least some of the importers today wouldn't consider messing with) that some of these schools bought over twenty years ago and are still using... I'll try to get rid of most of the clacking noises after straightening out their mangled crappy-prior-to-being-mangled linkage (along with their epic dents) and sending them back to the schools.

My personal instruments are just about as close to silent as one might imagine. I've gotten even worse than my dad was in regards to unnecessary noise.

I believe you exercised good judgment in declining having someone put abrasive on your rotor and spinning it around - when it's working perfectly well, particularly if they didn't convince you that they understood what what's causing the noise.

[TheBerlinerTuba]

Hallo valvehalla,

On the video of the valve with the backing plate, I can see horizontal scratches on the valve.
I've heard from colleagues in the USA that some workshops will first clean the valve and then use a brass brush or wheel to remove the patina, which leaves scratches like what I see in your video. If the tech was a bit too aggressive, the scratches will cause a light "hissing" or "scratching" sound.

The solution is to generally leave it as is and oil, and it will eventually go away. DO NOT LAP or HONE the valve.
Secondary, your linkages are at least 35years old and perhaps they are getting a bit worn. You can remove the adjustment screw and dab a bit of slide grease in there and that should quiet them down for a while.

And lastly if you haven't done so, try a rotor oil such as Hetman 12 or the Ultrapure blue rotor oil.

Hope that's helps,
Cheers from Berlin,
BerlinerTuba

[valvehalla]

Hello!

I guess you've tried moving the linkage by itself without it being hooked to the rotor.

That's correct; the linkage alone is essentially silent, and when turning the spindle without the linkage being hooked up I hear the rubbing sound.

I believe you exercised good judgment in declining having someone put abrasive on your rotor

DO NOT LAP or HONE the valve

Roger that, I will follow my intuition! :)

try a rotor oil such as Hetman 12 or the Ultrapure blue rotor oil.

Yes this is good idea and something I was planning on trying, just a little bit heavier oil. I usually use light piston oil down the leadpipe but on this particular valve the noise became louder, and ended using 11.5 rotor oil instead. Some 12 oil could indeed help.

About the older linkage: yes they are a bit finicky but I've found that a decent amount of grease shoved in there let's me tighten the end screws enough to remove most if not all of play, the clicking is extremely minimal. I've thought about getting some miniballs swapped out (M. Rick Denny had a pretty nice blog post about the process) but ultimately I really like the look the of those older linkages, and not too problematic to deal with (at least for now!).

Lastly, I'm still somewhat curious about the silver plating inside the rotor casing, does that look normal (or whatever normal used to be in those manufacturing years)? I can't see a reason why such a thin layer would affect the rotor's rotation, but just find it curious that there's any at all in there.

The horn is amazing and I'm happy (and inclined) to be able to preserve a bit of history for as long as I can, again I can't thank enough everyone responding and providing input.

Alex

[bloke]

This isn't a hard and fast rule, but instruments that are silver plated after they've been manufactured (in other words, silver plated as used instruments) and sold often have silver in the casings.

Quite a few manufacturers that sell a new silver plated instruments try to do the final valve fitting after the silver plating is done, so that the silver plating inside the casings is polished away during the final valve fitting.

The way the electrical current carries the silver, the amount of silver in casings isn't usually very much, but aesthetically it's not particularly pleasing to see it in there.

If you want an opinion that doesn't matter:
My view of silver plating instruments is that it's a mess. It tarnishes when touched by the player. When applied, it gets everywhere, some of the surfaces don't need it on them and probably shouldn't have them on them, and once an instrument is damaged, the silver plating becomes problematic... and tubas tend to be subject to damage more than other brass instruments due to their size.

Satin silver finishes which were popular in the distant past in America sort of served the same function as textured refrigerator surfaces which were popular in America a few decades ago. The satin texture sort of hid fingerprints. Bright silver instruments in America became popular when trumpet player Doc Severinsen (who also wore flamboyant outfits) sported a bright silver Getzen-made trumpet on the Tonight Show beginning back in the very late 1960s, and then it was off to the races. Wisely, most horn and trombone players haven't fallen for this gimmick.

[MiBrassFS]

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[bloke]

I don’t know what the rotor looks like, but the casing and adjacent tubing isn’t all that clean…

I see that - now that I'm on my laptop w/15" (horizontal) screen.

Last night, I was close to asleep, and looked at those pics on my phone's tiny screen (without my glasses).

This is a GENERAL (not specific) observation...I've made it before (because I post too often).

> Most people - who bring their personally-owned tubas to me - bring them to have them altered or repaired.
> ALMOST NO ONE - who brings their personally-owned tuba to me - brings it to me to CLEAN.
> A LARGE PERCENTAGE - of people who bring their personally-owned tubas to me - are in need of having their tubas cleaned.
(the 184 1st valve slide trigger job - posted here: That instrument was handed to me with the rotors not turning.)
> I've seen many posts (on this site) from people asking how they can AVOID paying someone to (really) clean their instruments properly.

To their credit, a local teacher ACTUALLY handed off their personally-owned instrument to me (actually, when I was running all those errands a couple of days ago - culminating with that dinner-hour gig) to have it CLEANED.

no...I don't particularly enjoy taking my own (particularly not rotary) instruments apart and cleaning them...
- takes time away from making money
- cleaning tubas is not particularly "fun", anyway
...which is WHY (every time I play one of them) I'll flood it with (very low-priced) oil (so called "ultra-pure paraffin lamp oil" - purchased by the gallon online, so it's new/fresh/odorless and not putrid), which prevents lime from adhering to the interior surfaces. Approximately every two or three months (as I've outlined), I remove their main slides and jet hot water through their valve sections (while moving the valves, etc. I'll follow up with a check and brush-cleaning of periphery areas (slide interiors, etc.) that tend to hold onto sludge.

[valvehalla]

I don’t know what the rotor looks like, but the casing and adjacent tubing isn’t all that clean…

Agreed on the tubing.

The rotor and bearing have both been cleaned in household vinegar.

The casing however was later cleaned up better than what shows in the picture, while with the tech and troubleshooting.

It is in my plans to get the horn chem cleaned professionally. Not super hopeful this will change much as it's more soft slime than anything, but it needs a bath anyways ;)

[MiBrassFS]

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