Valve Stroke

Discussion in 'Horns' started by Tootsall, Apr 29, 2005.

Do you think it would be helpful to have a table of valve strokes or should we continue to hang onto

  1. "Yes", I am willing to measure and post a reading

    100.0%
  2. "Maybe"... I would like to know the truth about others but don't want to know about my own horn

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  3. "Are you nuts!"? Why would I want to let go of a chance to argue over unsubstantiated and subjectiv

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  1. Tootsall

    Tootsall Fortissimo User

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    Yee HAW!
    On the Trumpetherald website I had been following a thread about "shorter stroke valves". This mechanical aspect of a trumpet valve block has intrigued me ever since I read the Denis Wedgwood website in which he discusses his "Ovoid" valves. http://www.deniswedgwood.com/index.html . His innovation changes the positioning of the ports through the valve pistons so as to provide clearance that minimizes the size of the "bumps" within those ports.

    Anyway... after reading the different posts about who has the "shortest" valves I got frustrated at all the techno-babble and suggested (apparently with some heresy!) that maybe they should actually MEASURE the valve stroke. I even posted the measurements that I took from my own trumpets to "get them started". Oh me. Only one person actually took and recorded a measurement (and he used a machinists dial indicator). One person (to his credit) took a machinist's rule to a store and compared a bunch of different horns but failed to record the actual results (he did say that they were all the same though!). Very quickly the discussion has once again regressed to one of those "my valves are faster (shorter, lighter...) than your valves" and nobody is actually posting NUMBERS. (check it out here if you have the inclination)
    http://www.trumpetherald.com/forum/viewtopic.php?t=35444

    So here is my proposal: be it resolved that since we (trumpet players) are generally obsessed with "numbers", (bore size, bell diameter, taper shape, blah blah), let us create an actual LISTING of valve strokes for the different brands of valve blocks! The method for measuring is dead simple and requires nothing other than a steel rule (or other accurate "ruler" with markings for every millimeter). You don't even have to pull the valves and attempt to measure "between ports" or any of that mumbo-jumbo.

    A valve stroke is simply the distance "valve up/valve down". Put the rule on it's end on top of one of the valves and note the measurement at a precise vertical location on the valve button (I'll suggest top or bottom edge where there is a sharply defined point). WRITE THE READING DOWN. Press the valve button DOWN and take another reading. WRITE IT DOWN. Subtract one reading from the other and *eureka*.... you have your valve stroke!

    My contention is that we "perceive" that the valves on this trumpet or that trumpet have a shorter stroke but that our PERCEPTIONS are colored by things like the "feel" of the valve, the response of the horn, the strength of the valve spring, the amount of wear, even the position of the valve block relative to our hand position and our finger "curl". The numbers may actually tell a far different story.

    Here's TM's chance to once again debunk a typical "trumpeter's myth".




    OK, as an engineer I'm a self-admitted equipment geek. Tough. Deal with it. My wife has to live with it. :D

    Edit: There is a prize for the person who can post what the apparent contradiction is within Wedgwood website and discussion on "Ovoid" valves. The first person to point it out receives a sincere "Attaboy" (or "Attagirl" as may be appropriate).

    Clue: we may have to start listing measurements to demonstrate this apparent contradiction.
     
  2. Bill Bryant

    Bill Bryant New Friend

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    Jan 26, 2005
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    I posted measurements on TH for a Bach Strad 37 and a Getzen Eterna Flugelhorn some time ago.

    http://www.trumpetherald.com/forum/viewtopic.php?t=30655&highlight=valve+stroke

    Measuring what the valve piston actually does is "real world" but may be a tad off from what the horn was designed to do if the felts or pads are worn. A better way is to measure a piston's port distance. This will give you the designer's intended piston stroke. (Use a precision tool for an accurate measurement.)

    Note: Be sure to measure the distance between the tops (or bottoms) of ports designed to line up with the same port in the horn, one on the up stroke, one on the down. On the 2nd piston this would be ports facing toward the mpc or ports facing the music stand, not ports facing the 2nd crook.
     
  3. Tootsall

    Tootsall Fortissimo User

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    Yee HAW!
    Agreed 100%, Bill. But a player senses valve stroke (and bases his comments or posts from his impressions) based what his fingers actually DO rather than what the horn was designed for. I could have mentioned the change to stroke that occurs when someone gets a PVA done but felt that the change would be so minimal (and the chances of someone actually getting a measurement from such an adjusted horn) that we didn't need to muddy the water at this point.

    If we started seeing two or three guys posting radically different numbers for the same make/model of horn then we could ask if they'd had a PVA or other valve rebuild performed.
     
  4. trickg

    trickg Utimate User

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    This is a great topic Toots. It has always seemed to me that Yamaha and Schilke have the shortest valve strokes, Bach is longer, and the valve stroke on the Benges was longer still.

    Whatever the difference, after having recently aquired a Schilke, I can say with some confidence that I play cleaner on the Schilke due to the valves. Whether this is a product of the valve stroke or a product of the action is a good question, but the fact that my playing is cleaner playing on a Schilke than it is on a Bach cannot be denied.
     
  5. Mr. Stomvi

    Mr. Stomvi Pianissimo User

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    Nov 14, 2003
    I think the Wedgewood site is somewhat full of engineering balony. Wedgewood claims that his valve travel is less than other manufacturers as if it was a big deal. According to his measurements his valve travel is 16mm or .629in and that Bach has a 16.12mm or .635in. That's not even a difference of one percent of the total valve travel between the two valves he mentions. I defy anyone to tell me they can "FEEL" a difference of .12mm in valve travel.

    As I mentioned over at TH, yesterday afternoon I had a chance to compare valves side by side from a Bach Strad, Vintage One, Yammie RGS, and my Stomvi Master. Using a flexible machinists rule which I always carry, valve ports were measured (top to top) to be the same on all the above horns. Last night I measured a Yammie student horn I had lying around as well as my Stomvi Master Bb using a dial caliper. Guess what. They ALL had the same valve travel when measured from top of one port to another (.635inch). Just what Wedgewood listed on his site for the Bach valve travel.

    As far as Wedgewood's other claims regarding air flow characteristics thru his valves, I find it difficult to believe that his ovoid design makes any difference at all. The pressure differential and air velocity thru the valve block is just too low compared to the other parts of the equation (i.e mpc bore and small end of the leadpipe). Perhaps if he had some air flow, volume or pressure differential numbers to back up the claims I might be more inclined to view his valve design as a real breakthru.

    Seth Moore
     
  6. Tootsall

    Tootsall Fortissimo User

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    Seth, as posted previously by myself, I've measured the Bauerfine (Eclipse) at 14.5 mm and my B1 Schilke at 15.0 mm. The Getzen 800 L cornet comes in at 16.5 mm. Using a machinist's rule I would NOT dare try to "guess" at closer than 0.5 mm. Now, if I had a dial indicator........

    Seth wins the "Attaboy". The Wedgwood site implies that the ovoids reduce the sizes of the "bumps" (which is true enough) but that it also results in a shorter stroke. Not so. The Wedgwood horns are undoubtedly superb instruments (as are almost all of the customs). But when it comes to physical, measured valve stroke, they are barely in the ballpark.

    Although I don't know if the lack of "bumps" promotes physical air flow, I will agree that the design might result in less "upset" of a particular node for a given note should such fall precisely "on" the location inside one of the valve ports. (just like a "dent" in a leadpipe can upset the tuning for a particular note).

    Seth's measurement of 0.635" equates to 16.129mm. (not that we're splitting hairs or hares or anything :-) ). So far the Eclipse (or Bauerfine....how DOES one spell that name correctly?) is the winner for short strokes with Schilke a relatively close second.

    Anyone else want to put some numbers up?
     
  7. Manny Laureano

    Manny Laureano Utimate User

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    Geez... I didn't know there were any myths about valve strokes.

    Thanks,
    ML
     
  8. nieuwguyski

    nieuwguyski Forte User

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    I went into this data collection expecting that valve stroke would be directly related to bore size. Nope.

    "Cadet" vintage pea-shooter cornet from West Germany (.440" bore) -- 14 mm stroke

    Conn 5A cornet (.485" bore) -- 14.2 mm stroke

    Conn 80A cornet (.485" bore) -- 15.5 mm stroke

    Schilke CX5 trumpet (.468" bore) -- 15.5 mm stroke

    Getzen Eterna Eb cornet (.460" bore) -- 15.75 mm stroke

    Getzen Eterna picc (.420" bore) -- 15.75 mm stroke

    Holton C150 pocket cornet (.453" bore) -- 16.75 mm stroke

    Then I started looking at the valves themselves, to see if the Conn 5A had huge bumps, resulting from having a huge bore and a short valve stroke. Nope, the bumps were merely flat spots, no worse than in the Schilke.

    My measuring tool was a dial caliper.
     
  9. Tootsall

    Tootsall Fortissimo User

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    Yee HAW!
    Now that's what I'm talkin' about! Real numbers. They force you to think rather than guess or imagine.

    While I was reading John's post I started considering his comment re: valve stroke related to bore size. One might likely assume that a valve stroke must be roughly equal to the bore size of the trumpet.... but not necessarily! Not if the diameter of the valve PORTS is different from the bore of the tubing! And don't forget that the piston has to travel slightly further than "just the diameter of the opening" to allow there to be a "sealing surface" (and to accomodate "PVA" adjustments and varying felt thickness!) to separate the port from the cylinder opening and so prevent leakage.

    (I was tempted to say "separate the port from the starboard" but I managed to resist. :D )

    Note that a worn or packed out top and/or bottom felt will allow a longer-than-designed valve travel. It helps if you can pull the second slide and confirm that things are lining up properly in the "down" position.

    I wonder if the "C" Schilkes have a different valve block from the Bbs. Anybody know? My B1 is very low hours since new so it is likely "just barely" packed in to the proper position.
     
  10. TotalEclipse

    TotalEclipse Piano User

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    Mar 2, 2005
    Brisbane in OZ
    Just did a quick check on some of my horns that are in reachind distance.

    1947 Conn 22B NYS__________________________15.5mm stroke
    1964 Conn 22B Victor_________________________16.0mm stroke
    1950's Getzen super deluxe tone balanced cornet__15.1mm stroke
    1937 Buescher Aristocrat______________________15.8mm stroke
    1960's Rex Bb_______________________________15.9mm stroke
    I made a mental note before I measured as to which I thought was the shortest stroke and the longest.
    I assumed that the Rex had the shortest.............wrong!
    I assumed the 22B NYS had the longest..............wrong again!!
    The problem I found was I also used a visual refference to judge my thoughts.
    The Rex has very large diameter buttons that make it look smaller stroke
    where as the 22B NYS has the small style ones that give it a tall look.
     

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