TromboneChat

I've had trombones with rotary valves for 40 years. Never had any trouble taking them apart, cleaning them, adjusting them, putting them back together such that they worked. Never needed any help with getting them the way I wanted them.

Until I bought my Kanstul 1662i. Very nice CR valves. Big, light, and very tight fitting. They work great until they don't. I've had to have this set of valves serviced 3 times in the last 5 years. I can take them apart, but I can't make them go again. When I put them together, they just won't turn. And something as simple as running water through the bell section might cause them to bind up.

I get that they're tighter tolerance, but what takes a valve that is working and suddenly makes it not work? Why do they continue to bind up? I feed them a regular dose of light valve oil. I need to be able to service my own valves. What do you need to do to tight new valves that you don't have to do to old loose valves?

I had problems with a valve on my Yamaha, even though I regularly used the Yamaha lubes. When I switched to Hetman (on my tech’s advice, a few drops down the tuning slide into the second valve every couple of days) the problem went away. Hetman’s 11 or 12. Anti-oxidants according to the tech.

Are you sure the core is fully seated? I run into a similar problem nearly every time I clean my Shires rotor. Also check and make sure the stop arm screw is real toight.

Sounds like the bearings are tapered. In this case getting the removable plate on perfectly is VERY important. A technique that was in my Mirafone guide may help.

Don't try to bang the plate in directly. Place it gently on the casing with the notches lined up. Now screw on the large cap. Tap the cap with a soft mallet and screw down further. Tap and screw until the cap doesn't turn further. This guarantees the plate is properly aligned to the bearing.l

I’ve had problems similar to this on my CR valves, too. I bought them for my Bach 50, and had them installed 7 or 8 years ago. My tech, Graham Middleton in Salem OR (a GREAT tech, BTW), recently serviced mine. I was using UltraPure, and Graham said I should switch to Hetman’s, too. My valves were VERY tight for the first few years. They are looser now but still have plenty of seal/compression. They’ve been cleaned, honed, chased... just about everything, but they are behaving now after this most recent trip to Graham.

I’ll have to try that technique, Bruce, next time I clean my valves. Thanks!

Ok, good to know that it's not just me. Any idea what the techs do to get them to work again? Do they just clean them hard? I sometimes have trouble just getting them to turn when placing the core in the casing. I've been using Hetmans, but I may have also used something else, and I know just getting water in one that was working fine caused it to bind up. Thanks all for the info.

I had to find out from a tech buddy that my olsen valves were getting caught up because i had them in reverse order and they were color coded to indicate which casing belonged to which rotor. He also said UMI had told him valves and rotors were made to fit to each other and weren't necessarily meant to be interchangeable.

Correct. Valves are not interchangeable. At least not high quality, correctly fitted valves.

hornbuilder wrote: ↑Thu Dec 10, 2020 12:11 pm Correct. Valves are not interchangeable. At least not high quality, correctly fitted valves.

The rotor is lapped into the casing isn't it, Matthew?

hornbuilder wrote: ↑Thu Dec 10, 2020 12:11 pm Correct. Valves are not interchangeable. At least not high quality, correctly fitted valves.

Be nice if every valve had an assembly number on the casing and on the core, but a lot of them don't.

That's why I always mark then during my first disassembly

Dennis. Yes, most valves are lapped into the casing they will live in. So, that means that even though they may have started out "the same" size (there is always "some" degree of variance, even in CNC machined parts) once lapped, they are different enough to not be.

John L. On single valve instruments, it is not uncommon to not have the rotor marked, but on multiple valve instruments, it is unusual for them not to be marked somehow.

Marc crammed. A sharpie is your friend! Or, even just a simple awl to scribe a mark of some kind.