Trouble with valve screws

[The Jackson]

Hello all, I come heavy with question.


I've been using a school-owned Yamaha 641 for a few months now. It's an all-around beater, but manages to hold together most of the time.

For about the past month, I've noticed that two screws on fourth valve (I'm sorry, but I don't know the specific names. Pictures at the end of this post) have been unscrewing themselves as I operate the valve. One time, I didn't notice it, and the screw came off and the paddle snapped back on me.

What could be the issue causing this? What course of action should I take to fix this? Any help at all would be very much appreciated!


Pictures (too large to post here):

http://img.photobucket.com/albums/v319/ ... 0_3000.jpg

http://img.photobucket.com/albums/v319/ ... 0_2999.jpg

http://img.photobucket.com/albums/v319/ ... 0_2998.jpg

[TexTuba]

[The Jackson]

I hear you on that, but I just wanted to know if there was anything on this that could at least provide a little bit of insight.

[Dan Schultz]

Those screws are subject to quite a bit of stress. But nevertheless, if they are properly tightened, they should not come loose on their own. Let your band director take care of it. You don't want to be responsible for breaking off one of the screws.

[The Jackson]

Yes, that probably would be the best course of action. Thank you!

[Art Hovey]

Unless your BD is a tuba player with demonstrated skill in rotary valve maintenance I would not expect him or her to be much help. I would suggest obtaining some "Lock-tite". Not the extremely hard kind, but the gentle kind. Put a drop on the threads, put the screw in, tighten it up gently, and let it harden overnight. It's like a glue that is designed to keep screws from coming loose in situations like this, but still allows the repair person to remove them without damage.

[The Jackson]

Hmm, that's very interesting. I'll definitely run it by him.