Remedies for Widened Valve Guide Slots?

[Rick Denney]

My 1976 B & H 4-valve EE flat makes much noise when the valves are going down and before they hit bottom and before they reach the top. If I press them half way down, I can feel some free play from side to side if I try to turn the valves. I changed the metal guides last year.

Any repair suggestions?

Unfortunately, I live very far from a repair shop that works on such tubas regularly. Any suggestions would be appreciated. Bill.

Any technician competent with brass instruments (even if they aren't tuba specialists) should be able to custom-fit valve guides to remove the lateral slack. I know that techs claim that if properly fitted, metal valve guides are quiet, but my experience is that nylon is always quieter.

Let's face it: If you play the tuba, you have to occasionally plan your vacations around passing by the well-known technicians, and work with them long in advance to try to reserve their time. The alternative is shipping. But valve guides are relatively easy.

Rick "for whom this is not a home repair" Denney

[Dan Schultz]

Refitting keys into worn guide slots can be pretty tricky. I've seen some very badly worn valve guide slots .... worn to the point that the deepest part of the slot was the only original width and the tops of the slots fell off to an angle instead of a straight side. If this is the case, you need to refit the keys so that they reach deeply enough into the slot to eliminate the side motion. I don't know off-hand what the screw threads are in the B & H pistons but I use a blank key that comes with a round head and a #3 thread. It is also possible to rework the key slot a bit by making it a dab wider. This has to be done with great care to insure the slot stays straight and true. Unless it's simply a matter of replacing the current guide, you should probably wait until you can see a good technician who can remedy the situation.

[ThomasDodd]

If you just had the quides doen, either they were not done correctkly, or more work is needed.

Giving the repairman the benifitt, the slots are probably worn. Since fixing that will tak a top-notch guy, they can also evaluate the previous work to be sure that the problem.

Can a broach be used to curt the slot wider? I would think so, but something is needed to maintain the shape of the casing. A top-notch shop probably has somthing the right size, or can quickly make something. The average shop probably won't.