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davewerden

Protecting Plastic Valve Guides

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Piston valve euphoniums and tubas need a guide on the side of the valve to keep it from turning within the cylinder. Older horns used metal guides, which were very sturdy but caused a rattling or clicking sound when using the valves. Newer horns have guides made from some kind of plastic, which are very quiet but subject to damage.

It is difficult to damage a plastic guide while the horn is assembled and being used. Most damage occurs when the valve is being replaced after oiling or cleaning. If the player is not careful to align the guide with its slot when putting the valve back into the cylinder, the guide hits the top of the valve casing. This can cause it to "mushroom" at the bottom - it becomes wider or thicker where it has struck the casing. If it hits hard enough it can even shear off.

uring an Army Band Conference, one of my former students who was the principal player in one of the top bands, came to me right before a scheduled performance. One of the euphonium's valves had stopped working smoothly. I took it apart and found that the guide was mushroomed at the bottom. Fortunately I had my trusty Swiss Army Knife and was able to re-shape the guide well enough to get the valve working smoothly in time for the performance. This was not a player who is rough on horns, so take this as a warning of what can happen at an inconvenient time.

As you get ready to replace the valve, be sure you can see where the slot is. Then just line up the guide so it goes smoothly into that slot. Avoid the much-more-common practice of letting the guide hit the top of the casing, then rotating the valve until the guide finds the slot. It is not hard to do it the right way, and it will take only a few seconds longer.

Updated 03-29-2019 at 07:24 PM by davewerden

Categories
Euphonium-Tuba Blog , General Tuba-Euphonium Blog

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