Cornet valve port alignment woes Quality Control?

Discussion in 'The Rehearsal Room' started by David Broad, Jan 10, 2018.

  1. David Broad

    David Broad Member

    I have been having real problems playing Cornet over the past few years. I was principal Cornet for 20 years in our village Band and played Besson cornets, the "Imperial Besson" predecessor to the 700, then my own Sovereign possibly a 921, and then a 927. More recently I have mainly conducted or played Euphonium.
    Around November it became clear we were short of Cornet players and I dug out the old Sov. Actually I went through all the spare Cornets and found a 700 was easiest to blow and sort of struggled through, though I ended up playing Horn on most Carol events.
    Now Christmas over I put the 700 back in the Bandroom and I idly wondered why it played so much better than the 927. The Instruments looked identical except a mobile 1st slide on the 927. Even the valves interchanged.
    So I swapped them and suddenly the 927 blew easier.
    I was intrigued, so I swapped them back, checked the felts, which were actually very thin, so I backed off the Valve caps, not finger buttons, off a turn and the 927 blew much freer, especially on bottom C but noticeably better all round.
    Further investigation showed the valve threads were two threads or thereabouts longer on the 927.
    10 minutes work with a sanding disc in my black and decker drill and they were the same length as the 700 and it blows much better with everything screwed down. I checked the old Sovereign a 1980 built model and it also played much freer with the valve caps loosened, and yet with the slides pulled I could see the valves still lined up perfectly with the valves down so after establishing how much the valve needed to be shortened I did that too, and it transformed the damned thing. I had been playing it since 1990.
    Which leads me to wonder just how many poor instruments just need a bit of physical adjustment, and what if any quality control existed at the old British factories.
    Maybe some other players have this problem without realising?
    Last edited: Jan 11, 2018
  2. Tom-King

    Tom-King Well-Known Member

    Lots of factors potentially at play here...

    For starters, valve position (in up or down positions) isn't just determined by one thing - there's a stack of different tolerances all interacting in a way that might cancel each other out, or might all pile up in the same direction and cause a misalignment.

    For example, let's take your observation (which appears to relate to the "up" position)... Well there are several things that could and would affect that - the tolerances in the valve cap itself (if the underneath/inside recess wasn't machined deeply enough or too deeply), the tolerances on the valve itself (the length of the piston itself, the length of the barrel soldered atop said piston), the overall length of the casing, the tolerances on the valve stem (if this is machined too thick or too thin) and then the thickness of the felt sitting on the stem....
    Now you may be starting to see that it doesn't take a whole lot of error on each individual piece to add up into a major misalignment - IF they're all/mostly pulling the alignment off in the same direction.

    Personally I'd have experimented with thinning the felts before I went at the metal with a B&D - cheaper to replace, easier to source, etc...

    Having said that, the first thing I'd have done (if I didn't already have one) is to go on eBay or Amazon and pick up a cheap "borescope" so I could actually see the alignment myself before messing with it.

    I'll stick a link to a previous thread also incase anyone finds it interesting/useful..
    Last edited: Jan 10, 2018
    2nd tenor likes this.
  3. 2nd tenor

    2nd tenor Well-Known Member

    With careful measurement and sketching out where parts are in relationship to each other (when the valves are depressed and when not too) I have noticeably improved a few instruments - one is my own and the others belong to my band. A burr free wire probe (‘L’ shaped) working from an adjacent valve bore through the connecting ports has been a help too, just be careful not to scratch anything up. No metal was cut, felt pads of the correct thickness were used, if required then standard thickness pads were thinned down. The link above from Tom goes to a really helpful thread with several ideas for the user to develop.

    In my limited experience it’s not at all uncommon for band instruments to have poor valve alignment. Given that it’s an easy and lasting way for a player to sound better I’m surprised that more folk don’t check out their instrument ....... however, I too was once part of that group that assumed everything was as it should be and, anyway, didn’t have the simple skills needed to check.
    Last edited: Jan 10, 2018
  4. David Broad

    David Broad Member

    Many thanks to Tom-King for the link I did a search before posting but I did not find it. I do note some valves are £150 each and some unavailable so be careful! I used a fine sanding disc in a Black and Decker hand drill to trim the valve rather than risk damage putting it in my lathe. I now suspect the 3rd valve on the 920 is not going down far enough so I will be fiddling with that next, possibly a washer on the thread under the finger button but there is absolutely no comparison between how the instrument plays now to before I started. It actually went back to Besson shortly after I bought it as it was so stuffy and I don't thing the valves had been apart, as in finger button shaft removed from valve in the mean time so it really is mind boggling.
    I wonder if a flow bench would show the issue?
    Might do wonders for some Chinese cornets.
  5. 2nd tenor

    2nd tenor Well-Known Member

    I guess that this is a reasonable place to ask a question of others about alignment although it might not relate directly to the OP’s instruments. Older instruments, say 80 years plus, are not always ‘blown out’ and some are still giving good service to youth and lower section / non-contesting bands. Some of those instruments use a tube like cork spacing buffer between the valve button and valve cap (they are mounted in the valve cap top). I’ve never seen such buffers for sale and they don’t appear to be easy to make yourself, does anyone know of particular suppliers (shops/companies) who stock them?
    Last edited: Jan 12, 2018
  6. David Broad

    David Broad Member

    I took some photos of my modified valve and a new example it is a few mm and look as if no allowance was made for the thickness of even the thinnest felts. Theb Instrument is completely different after the mods, I found it unplayable before, I would be struggling for breath after one line of a hymn tune and had massive difficulty with bottom C in particular. Now I can play an whole verse without any issues. I have been trawling the web for articles on how tubes resonate when different diameter tubes are joined and can't find anything, only bits about denting instruments to correct certain notes.

    See pics of a 920 Sovereign cornet the one with internal threads in the valves.


    I think most people use modern felts under the finger button instead. I was playing a 1927 Boosey Tenor Horn at Christmas and that had modedern felts now whereas it used to have those cork tubes. It has a great tone for Carols, much more Flugel like on high notes than the Sovereigns and the like
  7. 2nd tenor

    2nd tenor Well-Known Member

    As general information only my search for cork tube has produced no results but a search for cork washers has been more useful and maybe there might be some overlap. I used eBay, searched for cork washers, and found items in Germany and the USA - they were for instruments too. With a bit of luck (quite a bit) someone will know what was used on the vintage instruments, though at the moment I’m resigned to adapting felts and anything else that might work as and when the need arises.
  8. GordonH

    GordonH Member

    I make my own felts and corks. I have a set of punches for doing it. Bought the punches years ago and they come in useful for all sorts of things. Made a new coffee machine seal with them at the weekend out of neoprene!

    I bought a boroscope that fits on my mobile phone last year. Was £6.99 and it works really well. Useful for valve alignments and checking out other issues in instruments. Also used for identifying what was tuck down the back of a radiator. It is only 6mm diameter at the end so it goes through a cornet easily. It has LED's on the end too for lighting.
    Tom-King likes this.
  9. David Broad

    David Broad Member

    I just tried a 928GS Sovereign fresh from Besson after repair, same issue. I don't think they make proper allowance for the top felt.
  10. Douglas Sewell

    Douglas Sewell New Member

    Had a similar problem with those cork tubes under the finger button on a recently purchased old cornet. All notes were badly out of tune and on closer examination found that the valves were prevented from going down all the way Because of the extreme thickness of those cork thingamabobs. Removed them and substituted a thin felt water top and bottom of the spring to prevent clacking noises and all lined up and played fine. Well worth checking valve alignment.
  11. David Broad

    David Broad Member

    I have now found 7 Besson Cornets with the same issue. The valves don't come up far enough. The test is to slacken the top cap on the valve 2 complete turns and see if the Cornet plays/ blows easier. If it does fiddle with the amount the cap needs to be loosened for best sound and take that much off the valve stem.
  12. Tom-King

    Tom-King Well-Known Member

    Having a loose thread somewhere can affect the feel (perception of resistance / tightness of slotting) slightly as well....

    Your test doesn't control for confirmation bias - if you're expecting it to be better, you may well play more relaxed as a result which for most players will help you play better, whether the instrument itself is better or not.
    Ideally, it'd be much more reliable to blind test it with someone else swapping the felts out for thinner ones back and forth and see whether you can reliably pick the thinner ones.

    I still think it'd be far better to switch out the inner felts for thinner ones rather than hacking at the valves themselves... If nothing else, it's more easily reversed and less likely to affect resale value - I've modified bits and pieces in the past (mouthpieces etc) and even if they play significantly better for me, I know full well noone will pay anywhere near the same for them because they don't know what to expect, and I'd be exactly the same buying a modified mouthpiece if I didn't know who'd modified it (and/or who they are and how well they know what they're doing) or why.

    Bear in mind also (if relevant) that manufacturers expect felts to wear down a bit - they know that alignment will change over time so they'll often start with a felt that's slightly thick knowing it's going to thin down a bit with use.
    Last edited: Mar 8, 2018

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