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End Plate Fitting Issue


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#1 RAc

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Posted 29 December 2017 - 10:29 AM

Hello community,

 

towards the end of a wonderful whole-day squeezing session among friends yesterday, one of the reeds of my 55 button Aeola Wheatstone Crane (impeccably serviced by David Robertson 2,5 years ago) went deaf.

 

No problem, been there, done that. Open the respective end, locate the reed, clean it, put the thng back together.

 

Since I had to open up the end of the plate anyways, I played all the buttons on push and pull prior to doing it, making sure that if another reed or valve needs servicing, I can do it while I'm there. All buttons except the one played fine.

 

So I opened the box, located the deaf reed and cleaned it. The reed plate perfectly fit snugly where it was before.

 

The first thing that worried me is that the bolts wouldn't fit right anymore. When I open the box, I unscrew the bolts pairwise on opposite sides (and when I don't need to disassemble the action, I simply leave the bolts in their places so I don't risk mismatch), and afterwards, I gently and loosely fit all the bolts again opposite to opposite and only tighten all of them when every bolt has found its hole. So far, this has never been an issue, but the first two opposite bolts I tried to fit wouldn't find their holes, meaning one would but the other wouldn't. Since I'd never dare to exercise strength or force where things used to fit, I tried to very carefully wiggle the faces with only one bolt verly loosely fitted, but to no effect. The action plate pieces were never separated during the service.

 

After some investigation it looked as if the casing had expanded just a wee little bit; the hole that wouldn't accept its bolt was just a tiny bit too far on the outside. With just a very little pressure in that dimension (I tentatively fit one bolt, then held the assembly against my chest and gently pressed against the other side with my hand) finally the opposite bolt would slip in, and after I had those two fit, the other ones would go in without problems, and after fastening, the box played almost as before (but see below).

 

I'm sort of puzzled here. The box had been in its natural habitat for over 12 hours as this happened, and I don't think there were significant changes in temperature or moisture during the < 10 minutes the box was open, so there is no explanation for this sort of distortion. I've had the box open for much much longer that that without anything like that before. Was I just lucky before?

 

The other weird thing was that after I was done with the job, I again went through every button to make sure the box was fastened well enough so no air leaked between the chamois strips and action plate bottom - but this time another button was deaf! Now this one is one of the highest notes of the entire box which (in my understanding) is more susceptible to residue clogging, but obviously, it must have acquired the residue while I had the plate open!

 

Obviously, I should have preventively cleaned all of the (at least higher) reeds as I had the side open anyways, but I don't like to take out any reed without a justifyable reason (after all, ti's wear and tear on the reed shoes and their fittings).

 

So I'll need to open the box again and work on the newly feeble reed - but I'm sort of worried that one of the problems will show up again.

 

I find this ever so slight alarming, but then again, I'm somewhat of a hypochondriac when it comes to my boxes. Is the oberved behavior normal within the range of day-to-day usage?

 

Thanks very much for your answers in advance!

 



#2 d.elliott

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Posted 29 December 2017 - 01:55 PM

My first question, did you have both ends off at the same time? you have not got the LH end on the RH side by mistake ( we have all done it when distracted or in a rush)

 

my second question, have you got the end turned radially by a flat or two? (we have all done that too) I know that these are unlikely but it is worth asking.

 

Wood moves and what you describe is a problem most repairers will recognise. You will not want to ream out the bolt holes so this is what I would do:

 

  • push all the end bolts right into the action box, with the maximum amount of thread protruding under the padboard. 
  • line up the serial numbers etc to ensure that the end is being offered up min the correct orientation, Still all screws full sticking out under the padbard
  • engage the tip of one screw into it's nut and give it a couple of turns
  • move to the next but one screw and repeat, 
  • move to the next but once screw and repeat
  • move to the next but one screw and repeat.
  • you should have four screws started  and the four intervening screws not started
  • move to each of the not started screws in turn and start them by a couple of turns so that all screws are started but the end is stood away from the reedpan/ bellows frame.
  • tightening opposite bolts by a couple of turns at a time move round he instrument several times until the end is fully seated and the instrument is airtight.

 

 

Dave



#3 RAc

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Posted 29 December 2017 - 06:17 PM

Dave - thanks so much for taking the time to look into the issue, very much appreciated! Answers are inlined.

 

My first question, did you have both ends off at the same time? you have not got the LH end on the RH side by mistake ( we have all done it when distracted or in a rush)

 

=> No, only the RH was touched in the first place, so no possible mismatch here.

 

my second question, have you got the end turned radially by a flat or two? (we have all done that too) I know that these are unlikely but it is worth asking.

 

=> No, I had previously marked the alignment of the reed plate by a felt tip permanent marker and specifically checked the alignment of the two hand straps to ensure this would

      not happen (yes, we've all done that, so no offence taken whatsoever!)

 

Wood moves and what you describe is a problem most repairers will recognise. You will not want to ream out the bolt holes so this is what I would do:

 

  • push all the end bolts right into the action box, with the maximum amount of thread protruding under the padboard. 
  • line up the serial numbers etc to ensure that the end is being offered up min the correct orientation, Still all screws full sticking out under the padbard
  • engage the tip of one screw into it's nut and give it a couple of turns
  • move to the next but one screw and repeat, 
  • move to the next but once screw and repeat
  • move to the next but one screw and repeat.
  • you should have four screws started  and the four intervening screws not started
  • move to each of the not started screws in turn and start them by a couple of turns so that all screws are started but the end is stood away from the reedpan/ bellows frame.
  • tightening opposite bolts by a couple of turns at a time move round he instrument several times until the end is fully seated and the instrument is airtight.

=> Ok, so instead of going crosswise you recommend going clockwise but spaced. Makes sense, I'll try that next time. However, doing things acrost has always been my workflow so far (I've had both my boxes open so often I lost count), and never had a problem that way.

 

Dave

 

Again, thank you, much appreciated. Between the lines of your posting I believe to read that the behavior I see is not pathological in your (very very extensive) experience and judgement, so I can rest sound and not worry that I haven't seen this behavior so far?

 

Do you think that the second issue (the newly deafened reed during the service) may be a side effect, ot did the reed just catch a wrong grain of dust while I had the box open?



#4 Wolf Molkentin

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Posted 30 December 2017 - 02:03 AM

Rüdiger, if you don’t mind me, re the second reed not sounding, happens all the time when I‘ve been taking off an end to go for a reed issue - annoying, but not to worry IMO. I‘m therefore checking all the reeds on that side prior to fastening the end bolts.

Best wishes - Wolf

#5 Dana Johnson

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Posted 30 December 2017 - 05:10 PM

Rather than the bellows frame expanding, I would suggest that the end plate has shrunk due to seasonal changes. As long as everything is screwed together, the bolts transfer the stress to the sides, effectively doing what you did to get them back in. As soon as the end is unbolted, the bellows frame springs outward to relieve the stress it has been under. Traditionally constructed concertinas are often in a state of stress because much of the wood work is assembled at one humidity / moisture content , but is oriented in different directions that do not shrink and expand the same way. We used to make shop humidity gages of a strip of wood oriented long grain with a strip of wood oriented 90 degrees to it glued together. The cross grain expanded and shrank much more than the long grain, causing the strip to curve one direction when dry and the other when damp. Reed pans with radial chambers tend to potatoe chip if not at manufacturing humidity, or the Wood was not properly seasoned originally. The cross blocking in Jeffries style reed pans causes them to bow under similar circumstances. As long as the corner blocks are still glued and the end is bolted down, the clamping action keeps everything flat. The end and bellows frames are oriented so the grain goes around the circumference. It shrinks in thickness, but not in length ( sometimes causing the low shrinkage veneer to pull away from the higher shrinkage core wood. The wide expanse of the end suffers more change simply because it is so much larger than the other pieces. Laminated ends resist this to a great degree, but being glued to the action pan end frame, the unlaminated action pan often reacts to the stress by splitting between the pad holes that are aligned along the grain.
All this is to say that traditional concertinas should be kept assembled as much as possible. Leaving them apart for any length of time can cause trouble that in the case of a badly warped reed pan may be difficult to undo. Your end mismatch likely happened instantly, so you just do the best you can with it.
Dana

#6 d.elliott

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Posted 31 December 2017 - 02:33 PM

Dave - thanks so much for taking the time to look into the issue, very much appreciated! Answers are inlined.

 

My first question, did you have both ends off at the same time? you have not got the LH end on the RH side by mistake ( we have all done it when distracted or in a rush)

 

=> No, only the RH was touched in the first place, so no possible mismatch here.

 

my second question, have you got the end turned radially by a flat or two? (we have all done that too) I know that these are unlikely but it is worth asking.

 

=> No, I had previously marked the alignment of the reed plate by a felt tip permanent marker and specifically checked the alignment of the two hand straps to ensure this would

      not happen (yes, we've all done that, so no offence taken whatsoever!)

 

Wood moves and what you describe is a problem most repairers will recognise. You will not want to ream out the bolt holes so this is what I would do:

 

  • push all the end bolts right into the action box, with the maximum amount of thread protruding under the padboard. 
  • line up the serial numbers etc to ensure that the end is being offered up min the correct orientation, Still all screws full sticking out under the padbard
  • engage the tip of one screw into it's nut and give it a couple of turns
  • move to the next but one screw and repeat, 
  • move to the next but once screw and repeat
  • move to the next but one screw and repeat.
  • you should have four screws started  and the four intervening screws not started
  • move to each of the not started screws in turn and start them by a couple of turns so that all screws are started but the end is stood away from the reedpan/ bellows frame.
  • tightening opposite bolts by a couple of turns at a time move round he instrument several times until the end is fully seated and the instrument is airtight.

=> Ok, so instead of going crosswise you recommend going clockwise but spaced. Makes sense, I'll try that next time. However, doing things acrost has always been my workflow so far (I've had both my boxes open so often I lost count), and never had a problem that way.

 

Dave

 

Again, thank you, much appreciated. Between the lines of your posting I believe to read that the behavior I see is not pathological in your (very very extensive) experience and judgement, so I can rest sound and not worry that I haven't seen this behavior so far?

 

Do you t

hink that the second issue (the newly deafened reed during the service) may be a side effect, ot did the reed just catch a wrong grain of dust while I had the box open?

 

Ok, so instead of going crosswise you recommend going clockwise but spaced. Makes sense, I'll try that next time. However, doing things acrost has always been my workflow so far (I've had both my boxes open so often I lost count), and never had a problem that way.

 

The only reason I an suggesting going round alternate bolts is that you need to use the length of the bolts protruding under the pad board to take up any misalignment in the wood through the different 'layers' of wood work. at each stage as you go round you are only inching the action box towards the bellows frame allowing natural alignment to take place. If everything was aligned and the initial problem did not exist then I would have tightened up diametrically, once all bolts were started.

 

Dave






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