Dan wrote: "I am having problems with the change valve between low F and Bb in my F/Bb/f Schmid triple horn. It has a long lever and operates two valves on each side of the lever simultaneously. When I release the lever from Bb to F (I have the valves standing in F) there is often a little catch, or sticking. I have had two different repair guys look at it, both valves have been taken apart, and the strings and bumpers replaced, but it seems to be getting worse. Extensive daily oiling inside and outside the valves seems to help a little, but then the sticking will start up again for no reason. Has anyone run across this problem or does anyone have any suggestions?"
The following has to be done, in order, to be absolutely sure that this dual-valve linkage doesn't stick: 1. The rotors and horn have to be clean. Really clean. I recommend an ultrasonic cleaning, but a good chemical cleaning will do as well. 2. The rotors have to be seated properly in the bearing plates and oiled properly. Oil the bearings with a proper bearing oil. At this point the rotors should spin absolutely freely by hand. 3. String the LOWER valve (farthest from the mouthpiece) first, as normal. It's very tight in there, so patience is required. 4. String the upper valve just a bit LOOSELY. There should be the slightest amount of play. This is the critical part. If the upper valve stringing is too tight the valve will either stick or it will not return completely to both bumpers on both valves in both directions. Probably the strings were installed too tightly. It is a common mistake on this horn. The bumpers, by the way, will have nothing to do with this unless they are trimmed so poorly that they interfere with the rotor stop armature. The rotors are cylindrical in the casings, tapered in the bearings. An absolutely clean casing and a properly seated and well-oiled bearing are essential for proper operation of these rotors. This lever is very long, and the mechanical advantage of the spring is poor compared to the shorter dual-valve linkage. If the rotors and stringing are working properly, it will work properly. If your technicians don't know how to do this properly, take it to someone who does. Schmids are different from other horns, and if you haven't worked on them a lot you might not know all the little intricacies that make them "special". There is one last possibility, and that is that your horn is so old and used that the bearings are worn and loose. If that is the case, then you will need to get the rotors and bearings replaced. I doubt highly that this is the problem, but you did not mention the age of your horn nor how much playing it gets, nor how well it is maintained, so I only bring this up as a remote possibility. -- *Regards, Dave Weiner Brass Arts Unlimited* _______________________________________________ post: [email protected] unsubscribe or set options at https://pegasus.memphis.edu/cgi-bin/mailman/options/horn/archive%40jab.org
