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Stuck Button Issue

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Posted (edited)



I have a button that's giving me issues on an anglo concertina. It's my main G/A button on the left hand side 1st row. Not every time but often I will have it stay depressed or stuck in while I switch bellows or to another note with another button. I believe my issue is on the bushings under the fretboard; either where the button's guide pin enters the action board or where the lever arm goes through the button. I've seen/had instructions to use a paint brush with a tapered end to help get things centered straight and to avoid it getting caught up on anything; but the more I play around with it the less I'm sure of where I need to be making my adjustments. I've taken a photo and attached here. I really feel like my issue is more around the guide pin part where the bottom of the button has the red bushing that connects with the action board. I don't see how the lever arm going through the button with the bushings on either side would cause the button to stay depressed after I let go. 


The problem is practically non existant when I separate the action board from the bellows. Also when I remove the fretboard and allow the buttons to move around freely a few degrees either way; I don't seem to see where it's getting stuck. It mainly only happens when everything is back together and I'm trying to play.


Any advice would be greatly appreciated. Thank you!



Edited by McCarthy
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Things I check with a sticky button:

  • button/fret work bushing (I burnish with a tapered metal punch.)
  • button arm bushing.  The button must be able to move reasonably well on the arm as the angle changes up and down (burnish felt with an awl)
  • Check arm alignment with guide pin hole.  Arm must bisect hole when viewed from above.
  • Less critical with a metal button but check guide pin for burrs or guide pin hole for irregularities
  • On Lachenal hook and arms make sure the pivot plate is not excessively worn.  (Especially when the arm has a bend or two to clear other buttons)  Arm should not be twisted and primarily move up and down.
  • Make sure pad is clearing the inner rim of action box
  • After checking all the above, then, I'll adjust spring pressure if necessary.
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Posted (edited)

Thank you Greg, really appreciate your thorough post here.


I've taken the action board and fretboard off a few times and tried to adjust it; seems like I get it working and then it sticks again. I think from my picture I can kind of clearly see that the guide pin is not completely centered with the hole, I think it's getting stuck underneath and then at times when it pops back out and gets stuck ontop of the metal washer that's down in the guide pin hole. Slightly pushing it to the side puts it back into place. I'll have to take a closer look at the pad but it's got some room around all sides; I don't believe its catching.


What is the best way to align the arm with the guide pin hole? I often feel like its best to move the button one way or another along the track of the arm; through the arm bushing hole to get it centered but maybe I need to be pushing the arm over slightly to align it better? My picture is at a bit of an angle so maybe it doesn't do it much justice.


Maybe it's worth noting that if I push the button on its own in and out over and over alternating G and A; I often have no problems, but when I switch between that button to play another note on the right hand side; especially on the pull I often have the button get stuck in. Almost like the negative pressure the other note playing and pulling through the instrument is making the button stay depressed. A simple prod one way or another frees it back up. I'm sure it's a bushing problem more than anything though. 


Does it make sense in this case to remove the button off the arm? If so; what is the best way of doing that without damaging anything; I feel like I've seen it said before to remove the pad to free up the button but the pad looks glued in the assembly at the end of the lever where it's attached. Is it possible to roll the button out the guide pin hole slightly and then push it back off the opposite end off the arm where its seated? I'm cognisant I don't want to twist the arm at all. It's supposed to move up and down not side to side.


I'd assume that taking the button off is the only way to get a good awl/tool into the button arm bushing hole where the arm goes through the button. I don't seem to think there's enough clearance there to get anything in with the button slid on the arm. Should I try to ream out the guide pin hole if I were to remove the button?


Thank you very much!

Edited by McCarthy
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Sometimes, there can be some gunk in the bottom of the hole where the button guide fits and it's necessary to give it a bit of a clean out with a suitably sized drill. This is easy enough to do on a Lachenal where you can move the lever out of the way by pushing it through the post at the fulcrum.  That's probably also the easiest way to get the button off the end of the lever.  You can probably also rotate the pad around the screw thread at the end of the lever to clear it out of the way and create a bit of extra "headroom" at the button end.  With metal buttons, you're unlikely to damage anything.  Bone buttons need a little more caution...


(I note that there does seem to be some kind of metal (?) insert in the hole in the detailed picture you've posted - maybe this is just a bit tight?)


Aligning the lever with the hole is just a matter of bending the lever along its length somewhere.  Doesn't need a huge amount of effort to move it the fraction of a millimetre necessary.  Note where the button guide is binding a bit and bend the lever in the opposite direction


Alex West

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I don't like that the guide holes in the action plate have been lined with something, often these holes wear to a slight taper which is beneficial if not too excessive. To amplify a comment made by Greg,  the key must be able to freely rock on the lever arm to accommodate the changes in angle of the lever as the key is pressed down. Your keys seem tightly packed and the felt looks on the thick side. This is particularly important on the shorter lever arms. Some times this causes the whole arm to push up and down in the pivot post aperture rather than pivoting properly as designed. I would also encourage you to check the key travel distance, if it is too much then the guide pin on the key may be too high in it's hole, and/ or any reduced freedom of movement of the arm in it's cross bushing through the key will be made much worse. 


I would also check the key height against the others around it, the pivot post tang might be backing out of the action plate.


  Finally Greg's comment about aligning the axes of the end plate hole, the guide pin hole and the lever arm is essential for free movement of the action elements. 

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Thank you everyone for the assistance. I was able to resolve my button issue with your support and instructions. Some combination of the pad getting a little snug against the inner rim of the action box, the button guide pin hole needing to be cleaned/rodded out and burnishing the bottom button bushing into a more compressed form seemed to help. I also ended up having to try to gently push the button side of the lever arm over just slightly to make sure the arm was in position with the guide pin hole. Now I can practice on this conertina. After an hour+ of practice I didn't have any repeat issues so I hope I've resolved that issue for good. 


I have a reed issue on a low E that I'll need some help resolving. I'll save that for another thread with pictures and maybe an audio recording. I think it's a reed tongue getting caught or something of that nature. Separate topic though. 

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