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Yesterday I was concerned about a rattle in my Holton 345. I have worked my prodigious derrière off to get this horn to play closer to its potential. I have been quite pleased with my results.

Mostly.

So I was practicing, as I said, and at the end of every high Db or low C, there would be a light rattle that lasted about a half of a second. It was loud enough to hear but too short to locate. I moved into two different rooms as I thought it was sympathetic vibrations from things on or near the walls. It was probably not audible in the concert hall, even by our bass trombonist.

But it bugged me to no end. I suspected that the worst joint on the tuba to re-taper and to correct the fit in the ferrule must have a gap that I fed too much solder into, causing there to be a solder dingleberry, and that was flapping around inside the beast.

For the first 20 to 30 minutes I thought I had knocked my bell wire loose enough to vibrate sympathetically. My wife and I used an engine stethoscope, I moved around, aiming the bell at different surfaces, I pecked at the low C short and crisp, over and over, to have as little tuba and as much rattle as I could generate. No good. It was audible but very faint. But it *was* there.

I peeked through the bottom valve cap vent holes to see if one of the springs was out of its recessed home. It all looked fine to me.

After an hour of this work bore no fruit I gave up and decided to look for it after this upcoming set of rehearsals and concerts.

Long story short: It was the 4th valve spring. The piston end of the spring was slightly unseated so that the coil was banana-shaped and would vibrate on certain notes. The plastic coating was preventing me from localizing this vibration. It was very faint, and the metallic aspect of the sound was being attenuated enough by the plastic coating that it sounded like it is was coming from INSIDE the bugle somewhere. All I had to do was remove and reseat the 4th piston, et voila! no more noise.

Boy, I felt stupid!

Perhaps a year ago, I had a piston that was sticking every once in a while.
This was occurring on a particularly trouble-free instrument, and I hadn’t handled that instrument roughly in the least.
It took two or three weeks, but I finally found a hair between the piston and the casing.

Being a cheapskate, I usually install used Yamaha springs in my personal instruments, being that they never wear out - yet some people insist on new ones every so often. A fringe benefit with used ones is that the plastic coating on the ends is usually decayed (often, the feature which triggers people to have them replaced), which makes that plastic easier to peel off, as that plastic often causes problems.

bloke wrote: ↑Wed Feb 09, 2022 11:05 pm I usually install used Yamaha springs in my personal instruments....

Tuba/Sousa springs or Euphonium??

Three Valves wrote: ↑Thu Feb 10, 2022 8:50 am

bloke wrote: ↑Wed Feb 09, 2022 11:05 pm I usually install used Yamaha springs in my personal instruments....

Tuba/Sousa springs or Euphonium??

yes.
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(Yamaha euphonium springs are plenty stiff enough for properly-fitting front-action pistons (as front-action only overcomes friction, rather than having to both overcome friction and gravity), and their slightly smaller diameter tends to fit in more other makes' bottom caps' spring depressions.)

Similar with my oboe, but a longer resolution. The silly octave key was sticking open, most of the time, and putting a rubber band on it to hold it shut worked. In the past the oboe had had an unfortunate contact with a tile floor, keys down, and I thought it had all been straightened out but this one thing kept jerking my chain. Since there is no one here who is good with double reeds, I honked up to Phoenix (two hour drive) to take it to the one nearby person with a good reputation. I handed it to her and would not let the employee touch it. Later went back to get it to find out the tech had worked on it. They put a heavier spring in it. When there, it worked ok, but when I got it home, back to being sticky. Four hours of driving, $60 out of pocket, problem not solved. I talked to bloke about having Mrs bloke work on it, talked to her, and she was pretty busy. Eventually I just took it apart; as soon as I got the screw loose it worked fine. I figured the screw was bent somehow, but I took it out, wiped it off, put it back together....and voila, no more sticking. There was apparently invisible smutz on the screw because I have had zero problem since. That's about in line with Doc's original saga, I think, but he didn't drive four hours and pay an idiot $60.
For the non-oboe people: the octave key is basically a rocker, like the rockers in an overhead cam engine. Screw in the middle, rocks back and forth. Unless it has smutz in it.

LOTS of musical instrument repair danger, out there.

bloke “NOT a member of any so-called ‘guilds’ “

Must be vibration season - had one yesterday that was simpler & stupider.
Checked the usual suspects: lyre screw, valve caps & buttons, slide guard screw, trigger assembly screws. Ended up being the metal draw-string aglet on a new pair of sweat pants buzzing on the bottom bow. On the one hand, the rugged anti-fray is a nice touch on the value-priced Costco sweats. But tucked inside (my usual preference), the cold metal tips swing to and fro . . .