 The Oboe BBoard
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Author: mberkowski
Date: 2017-07-10 05:19
Hello all,
While I was trying to sort out an A#/B trill in the middle octave, I noticed a difference on my conservatory system Covey oboe between the LH G# key and RH G# side key.
When I finger middle-staff B and depress the LH G# (pinky), the A key (LH2) closes completely. I'm using that as my trill along with RH1. But depressing the RH G# side key, the LH2 does not fully close. I'm looking for and adjustment screw which might affect that linkage but not finding anything except perhaps the height of the bridge key (F# - G#) screw. But any change there has much more serious consequences. I don't see any missing cork on levers which might affect that link either.
On my Selmer instrument, the RH G# side key does close the LH2 A key.
So I wonder:
Does this matter on the Covey? Since that A#/B trill requires RH1 also be depressed, making it impossible to use the RH G#, would I ever actually need it to close the A?
If it does matter, is there an adjustment I can make to cause RH G# to close the A? I do have maintenance scheduled in about 6 weeks.
Thanks for your input!
Michael
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Author: Chris P
Date: 2017-07-10 13:41
It's not always possible to make the side G#-A trill key close the LH2 fingerplate - some oboes it's easier to achieve this than other depending on the linkages.
Some oboes have a clutch on the Ab-Bb trill mechanism (the linkage from the G# key to the LH2 fingerplate) and this can be adjusted so the side key can close LH2, so long as it doesn't close the venting down or cause double action between LH2 and the C key. The clutch is usually near the LH3 fingerplate by the LH3 B-C# trill key and either has a small adjusting screw on it or is a plain clutch with no adjusting screw.
If there's no clutch and the Ab-Bb link is on a single key barrel, then it's adjusted by bending the link to make it work. That has to be done carefully as the key barrel can bend and bind on the rod screw.
It's not the end of the world if the side G#-A trill key doesn't close the LH2 fingerplate as it's not really meant to, but it is a bonus if it does - I usually aim to make it do this wherever possible.
The linkages and levers are all fairly short and movement isn't great around the G# key, so sometimes even getting enough venting on the G# pad can be a challenge.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: Chris P
Date: 2017-07-10 14:32
Also if the opening of the G# pad cup is limited by the F#-G# adjusting screw arm from RH1, then that will prevent the G# key (LH) from moving to its full extent which will also prevent the Ab-Bb trill linkage closing the LH2 fingerplate compared to holding the LH G# key down.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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Author: mberkowski
Date: 2017-07-10 15:43
Thank you, Chris.
I located the clutch you mentioned and I can see the effect it has between the left G# and LH2. I'm not going to attempt to change it for the side key.
I notice now that if the oboe isn't assembled, the side key *does* close LH2. So it appears that the F#-G# arm is hindering the side key from rising as high as it would need to for LH2 to close. Since that link is in proper adjustment and functionally a lot more important, I'm just not going to worry about the side key now. I'll mention it to my repair tech later this summer.
Michael
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Author: Chris P
Date: 2017-07-10 16:21
If the RH1 fingerplate isn't opening enough, that can also have an effect on the venting of the Bb and C keys on the top joint.
They should open to 2mm and the RH1 fingerplate should open a fair amount more plus have some lost motion (double action or free play) between it and the con bar (the bar on the side of the top joint) and also a bit of free play once the Bb and C keys are open.
So when closing RH1 slowly, you should feel two distinct moments where there's some lost motion as it starts to move and just before the pad closes. The upper end of the con bar should also not make contact with the top joint.
I set up the top joint main action first, then set the con bar in relation to the RH1 linkage so there's a tiny gap between them. Then I fit the pad in the RH1 fingerplate so it's the correct thickness taking into account the amount of shellac and the amount of free play left in the con bar when RH1 is held down. Then it's a case of setting the adjusting screw on the F#-G# link once the RH1 pad is in and it's all regulating well.
On some oboes I have to alter the shape of the various G# linkage pieces to get more venting on the G# pad and make it work with the other keys linked to it. Some oboes are easier than others depending on the shapes and lengths of the linkages.
Former oboe finisher
Howarth of London
1998 - 2010
The opinions I express are my own.
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