Loose Valve Stem Repair Question

[tubamaniacRI]

Hey Now

I got a Conn sousaphone and the third valve stem wont screw in tight anymore. It keeps falling out at the most inappropriate times.

Any suggestions on a good cheap fix? I am thinking glue or soder but don't want to permently wreck it.

Thanks in advance.

Greg

[tubamaniacRI]

Thanks I guess I will bite the bullet and bring it to a pro. thanks again

[Dean E]

. . . . I got a Conn sousaphone and the third valve stem wont screw in tight anymore. It keeps falling out at the most inappropriate times. . . .
Greg

You have a couple of options.

The really quick fix is to lightly deform the male threads on the valve stem with your favorite instrument of destruction (light hammer, pliers, bench vise) and screw it in.

Another method is to buy a valve stem (the right height-it might have to be custom made by someone good on a lathe) with larger male threads, tap out the valve body to the larger size, drill out the upper valve cap to clear the larger stem, find a suitable finger button, and install the correct felts and washers to align the piston with the tubing. Good luck finding the right tap.

Yet another method is to buy some junker Conn sousas from the auction site until you find a third valve that fits or can be lapped. How lucky do you feel?

[Rick F]

Short of taking it to a repair tech, you could try wrapping a piece of Teflon tape around the threads of the stem. (You can find Teflon tape in any hdwr store). This should make the threads grab a bit more without making it impossible to remove the valve stem when you needed to. The Teflon tape can be removed easily too. Just be sure to trim any excess tape that might stick out above the valve so it doesn't interfere with spacers/felts/washers.

Just a thought.

[Dan Schultz]

'Quickie' valve stem repairs should be done only as an emergency measure. The proper way to fix the problem is to apply a bit of silver solder to the remaining threads and retap the thread OR bore the damaged thread out, solder in a brass insert, and tap a new hole. Both of these operations need to be done in a lathe or other device to hold the piston to make sure the new threads are in the center and straight with the axis of the piston. If the stem is a bit off center or leans one way or the other, it's going to bind on the valve cap. The worst case would be for the piston to receive further damage from 'the cure'.

I've seen a lot of these 'quick' fixes... usually done by band directors in an effort to either save the expense of sending the horn to a repair shop... or just to keep the horn going for an upcoming performance. Neither reason is a good excuse since this repair would probably only cost $25-30 and maybe a couple of days to work through the shop.

[tubamaniacRI]

Thanks for all the excellent advise. Found a pro to do it for $25. I am thankful for all the solutions. I am sure they will become useful in a future valve stem emergency.

Peace
Greg

[Dan Schultz]

Thanks for all the excellent advise. Found a pro to do it for $25. I am thankful for all the solutions. I am sure they will become useful in a future valve stem emergency. Peace Greg

EXCELLENT!