Low brass players and teachers know well the sound of noisy, poorly-maintained rotary valves. That annoying “clackety-clack” has been a blemish on many tuba and trombone ensemble concerts, to say nothing of the propensity of poorly-maintained valves to “freeze” at inopportune moments. While properly lubricating rotary valves is somewhat more involved than doing so with piston valves and is needed less frequently, it still must be done regularly in order to maintain quiet and smooth valve action.
- Small screwdriver (usually flathead).
- Hetman #11 Light Rotor Oil (or, if preferred, “regular” valve oil).
- Hetman #13 Light Bearing and Linkage Oil (or other rotor oil of your choice, provided that it is a thicker oil with a needle-type applicator).
Lubrication Instructions for Rotary Valves
Trombonists should place the slide away from the bell section; tubists will be able to “jump right in.”
First, remove the top cap from the valve and place a few drops of Hetman #13 (or other rotor oil) on the end of the spindle. Replace cap.
Second, turn the instrument over, remove the stop arm screw from the other end of the spindle, and place a few drops of Hetman #13 (or other oil) into the threaded hole. Replace screw.
Third, place some of this same lubricant on the various connections in the linkage.
Finally, squirt a fairly liberal amount of Hetman #11 (or a more liberal mount of “regular” valve oil) into the valves themselves, either through the handslide receiver (on the trombone) or through each valve’s tuning slide (on the tuba). Move the instrument about in order to ensure that the oil does run into the valves, all along working the valve buttons. Allow any excess to run out of the instrument.
Trombonists might want to place the bell section alone on a trombone stand for a while after completing this process, so that any excess oil will run out of the bell section and onto the floor, rather than into the slide section, where this oil would almost certainly “gum up the works” after mixing with the handslide lubricant. Replace the slide section after all excess oil has run out of the bell section. Tubists can more or less skip this step, as any excess oil will collect in the tuning slides for each valve and be easily expelled from there.
Other, Related Valves
The past thirty years or so has seen the introduction of a large number of “boutique” valves for trombones (and, rarely, tubas), including axial flow (or “Thayer”), Hagmann, Miller, Greenhoe, and others. While the relationship is more or less obvious depending on which of these valves you have, all are based to one extent or another upon the design of the rotary valve, and all are lubricated in essentially the same manner as that described above.
The above provides a concise but more or less complete guide to regular lubrication and maintenance of rotary (and related) valves. The remainder of today’s article will address important but less frequently necessary procedures.
Maintaining Proper Valve Alignment
When an instrument equipped with rotary valves has previously played well and later begins to become “stuffy,” one or more of the valves might have become misaligned. This is usually caused by normal “wear and tear” of the cork or rubber bumpers, or even the loss of one or more of these. To check if alignment is the problem, remove the valve cap and look at the bearing plate, spindle, and casing. There will almost certainly be two or more sets of “notches” that you will see. One is a notch on the edge of the valve casing, with a corresponding one on the bearing plate. Make sure that these are “lined up” before proceeding.
While there are sometimes variations on this setup, you should see a pair of “notches” on the spindle, placed at a 90-degree angle to one another, and one (sometimes two) corresponding “notches” on the inner edge of the bearing plate. When the valve is disengaged one of the “notches” on the spindle should be aligned with that on the bearing plate, and when it is engaged the other should align with the bearing plate. If the valve is misaligned in either or both positions, the bumper where the stop arm rests in that position should be replaced. To do this, simply cut a piece of cork or rubber to the needed shape and thickness and place it on the instrument in place of the old bumper. While friction should be sufficient to hold the bumpers in place, a small drop of super glue can be added if desired.
(The above procedure should work with all of the valve types referenced except for axial flow valves. For advice about aligning those valves, or if in doubt about any of the above procedures, consult a qualified technician.)
Trombone rotary valves rarely have string linkages these days, and for tubas this is a rarity, seen only with certain “historical” instruments. Rather than “reinvent the wheel” on this topic, I will direct the reader to a very thorough description of the restringing process provided by Osmun Music.
I do recommend that, rather than the “rotary valve string” sold by music stores, players with string linkages purchase a supply of 50lb. test weight woven fishing line. This type of string can be purchased very inexpensively at sporting goods stores or at “big-box” retailers such as Walmart or Target. A single purchase should yield a “lifetime supply!”
Rotary Valve Disassembly and Reassembly
Axial flow valve disassembly is quite straightforward. Remove the tuning slides, loosen the nuts on the braces nearest the tuning slide, loosen the lock ring, and disconnect the linkage, and the valve should come out easily whenever cleaning is needed.
Disassembly of rotary valves and the other types of valves mentioned here is more complicated, and honestly, I do not recommend that most players do so themselves. This process is best performed by a qualified technician, and some of the “boutique” valve manufacturers state in no uncertain terms that valve disassembly is a “don’t try this at home” matter.
However, if you would like to at least familiarize yourself with the process, take a look at these two videos by Dr. James Boldin, Associate Professor of Horn and Music History at the University of Louisiana at Monroe, and my next-door “office neighbor” when I taught at ULM. As with all of Dr. Boldin’s work, these videos are thorough, clear, and helpful.
Clearly, rotary valve disassembly and reassembly is a complex matter; again, I recommend leaving this to qualified repair technicians. Happily, as long as the valves are lubricated regularly and the instrument kept relatively clean, the disassembly process should be a rare necessity, indeed.