Adjustable Valve Bumpers DO exist !

[2bobone]

I was delighted to see photos posted of a trombone with "adjustable valve bumpers". The original post was "What was the most crazytrombone you've ever played ?". I was totally unaware that such a set-up existed when I posted a drawing a couple of years ago of an idea I had for such an arrangement. I was amazed at how similar the proposed setup and the existing setup are. I've posted a copy of the original post's photo and the original drawing of mine. Someone did a great job on that horn ! Valve alignment at the twist of a screw !

Valve Bumper Plate.PNG

[Crazy4Tbone86]

Yes, I believe the new Caidex valves by Willson have an adjustable valve bumper system as well. I agree with you that it is a cool concept. Much better to manually adjust them with a screwdriver/hexagonal wrench instead of trimming the cork or rubber bumpers.

[Posaunus]

I was delighted to see photos posted of a trombone with "adjustable valve bumpers". The original post was "What was the most crazy trombone you've ever played ?" I was totally unaware that such a set-up existed when I posted a drawing a couple of years ago of an idea I had for such an arrangement. I was amazed at how similar [my] proposed setup and the existing [french made custom valves] are. I've posted a copy of the original post's photo and the original drawing of mine. Someone did a great job on that horn ! Valve alignment at the twist of a screw !

Bob,

I had exactly the same thought when I saw that photo - why aren't all valve bumpers screw-adjustable?
Someone should have followed through on your idea. How about it, valve manufacturers?

[Burgerbob]

Bob,

I had exactly the same thought when I saw that photo - why aren't all valve bumpers screw-adjustable?
Someone should have followed through on your idea. How about it, valve manufacturers?

A lot of time and expense machining little bits. Much cheaper to pass that on to the consumer to trim bumpers.

[meine]

Yes, I believe the new Caidex valves by Willson have an adjustable valve bumper system as well. I agree with you that it is a cool concept. Much better to manually adjust them with a screwdriver/hexagonal wrench instead of trimming the cork or rubber bumpers.

Indeed, the Caidex have adjustable bumpers.

[LIBrassCo]

The caidex ones are really quite fantastic

[BGuttman]

Bob,

I had exactly the same thought when I saw that photo - why aren't all valve bumpers screw-adjustable?
Someone should have followed through on your idea. How about it, valve manufacturers?

A lot of time and expense machining little bits. Much cheaper to pass that on to the consumer to trim bumpers.

In the grand scheme of things that's really not true. Look at how many pieces-parts are in a valve. The adjustable adds only a few more.

[OneTon]

Do many valve sections or trombones with valves get traded off because the witness marks don’t line up?

[Crazy4Tbone86]

Do many valve sections or trombones with valves get traded off because the witness marks don’t line up?

Yes they do! I was given a set of Bach 50 independent rotors for free because the owner thought they were horrible. It turned out that the witness marks on the second valve were off by at least 30-35 degrees. I had to cut slots in the cork plate so the whole thing could be rotated substantially. I made new (accurate) witness marks and the valve set worked quite well.

The only thing about that valve set is, when I sold it, the owner had to know which witness marks to use. Well…….actually, it would become instantly apparent if the wrong witness marks were used.

[Burgerbob]

In the grand scheme of things that's really not true. Look at how many pieces-parts are in a valve. The adjustable adds only a few more.

Anything to cut costs is going to be used

[OneTon]

In the grand scheme of things that's really not true. Look at how many pieces-parts are in a valve. The adjustable adds only a few more.

Anything to cut costs is going to be used

That is especially true when dealing with myopic managements. On the other hand, the Toyota Production System leans (pun intended) toward eliminating variability and waste. Shaving cork or rubber is fiddly. Even if a time/cost study were to come close to a push, some of these adjustable bumpers are cool. And cool sells instruments.

My ear to the rails says Bach may be listening. Well, hope springs eternal.

[Sesquitone]

I am the conceptual designer of the CAIDEX valve--and, yes, that is an all-caps acronym for Constant-Area Internal Ducts of Elliptic Cross Section (with the CS replaced by X for easy pronunciation). My co-designer, Morteza Vatani, takes my rough sketches and equations and creates the code used for machining the parts; the two-part stops are no more expensive to make than a standard single part with double cradles. The usual "technique" of using oversized inserts and trimming with a razor is inaccurate and frustrating--especially when you trim too much and have to start over! The CAIDEX stops allow you to adjust in both clockwise and anticlockwise directions. An optional clear plastic dome in the end cap allows the player to check, at a glance, that the rotor is precisely aligned; if not, it is a quick fix with an Allen key. I would be happy to send more details to anyone who contacts me directly (via email).

Benny Leonard
[email protected]

[timothy42b]

Just a comment for those who don't recognize the name.

Sesquitone was a long time member of the old OTJ Forum, now here on the chat with a new login name.

Welcome back.