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arkwright

Action pin pulled out -- how to repair?

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This photo is not my concertina;  I copied it from Alex Holden's web site.  I will use it to illustrate a problem I have and ask for suggestions.  You can see a video on Alex's web site at this link:

https://www.instagram.com/p/BjC2Rpeg72K/

The levers are connected by rivets to the "action pins".  Each action pin is hammered into place like a nail.   Now, the spring is always pushing upward on the lever, and this upward force will tend to pull

the pin out of the wood.  When this happens, the button sticks up high and the pad doesn't cover the hole.  This happened to my 1907 or 08 Crabb anglo, and  I fixed it once by pressing the pin down into its hole, but it came loose again.  My inclination is to reset it with a tiny drop of "crazy glue"  but I am leery of doing anything irreversible. 

 

Has anyone else experienced this problem?  What's the best way to fix it?

Alex Holden concertina action.jpg

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Your instinct sound about right to me, though not sure what “ crazy” glue is.  Thicker consistency super glue would be OK. If the post seems quite loose in the hole a sliver of wood (this sort of thing was a great use for matches in the old days) placed in the hole first will take up the slack. When you hammer it back in (if it will push in by hand I think it is too loose) be careful as a spurt of superglue could be forced out under pressure and it could end up anywhere ( remember the golden rule of OH&S, “first cover remaining eye”). 

 

Next thing to think about is why the post is coming out. It could be the wood has shrunk from being too dry or it might be that the spring pressure for that lever or the whole instrument is a bit high. It is common to find post issues when a broken spring is replaced with a safety pin, which has the benefit of looking a little like a concertina spring but they are usually made of much stronger materials and will lift the post out over time. 

 

Your fix is not irreversible because you can always drill the damaged material out and epoxy in a dowel of the same size and redrill.  

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I've had this happen.  I found that pressing the pin back in (gently holding the pin using a pliers to allow more than simple finger pressure, but not hammering) worked for a while, but eventually it worked loose again. Glue will help, but since the hole is still tight enough that just pressing the pin back in holds it for a while, then you probably don't really need to use a cyanoacrylate glue, if you are concerned about irreversibility.  A tiny film of a far less aggressive glue such as PVA (I used Elmer's clear "school" glue) will likely offer enough additional bond to hold for a good long time; it has worked for me.  And I know I could pull the pin out without damage if there was ever a reason to do so.

 

With similar repairs in other applications, a variation of the match (or toothpick) trick I've used to get a tight fit in a loose hole is to add a tiny scrap of paper instead.  This works if the extra room to be taken up isn't quite enough for even a sliver of matchstick.  The slightest coating of a water soluble glue applied to both sides of the scrap of paper before inserting it into the hole will also lubricate the pin insertion (while the glue is wet) while improving the bond as the glue squeezes in between the paper fibers before it dries.

 

I must admit my experience with concertina repairs is still limited though!  I've seen Chris Ghent comment here often enough to expect he knows what he says.  And I admit I have fashioned a couple of safety pins into spring replacements, which he warns about.  I did however already know not to use too strong a spring, because of my experience with the loose pin.  So I do think the tiny little brass safety pins I found seemed a good match to the desired spring pressure, and therefor for me these have not yet caused a loosened pin.  Dry air in winter causing wood to shrink has occasionally been an issue where I am now, but for other reasons in my case.

 

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I believe Krazy Glue is a brand of cyanoacrylate/superglue. I have used superglue for this job several times and not had one come back yet. Note that not all superglue is created equal, and the really cheap tubes are IMHO a false economy. I'm currently using "Everbuild Industrial Grade Superglue GP" (medium viscosity). If you keep it in the fridge while not in use it lasts longer.

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On 3/29/2019 at 3:24 PM, Tradewinds Ted said:

I've seen Chris Ghent comment here often enough to expect he knows what he says.  

 

Not the best reason for a recommendation..!  

 

There are others who give advice here who know their stuff but for my money if you want great advice ask Theo. In all the time I have been reading his posts here I have not seen him put a foot wrong. 

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Thanks Chris!

I like to try first with a sliver of wood to tighten the hole, and if possible avoid using any sort of adhesive.   I would also advise against using a hammer to insert the post. It should be possible to press the post into place.  You can make a simple holder for the post from a piece of hard wood with a slot cut into the end grain to hold the lever and all of the post except for the pin. 

  • Thanks 1

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Posted (edited)

Sorry mis-posted in error.

Edited by Tiposx
Old age

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5 hours ago, Theo said:

Thanks Chris!

I like to try first with a sliver of wood to tighten the hole, and if possible avoid using any sort of adhesive.   I would also advise against using a hammer to insert the post. It should be possible to press the post into place.  You can make a simple holder for the post from a piece of hard wood with a slot cut into the end grain to hold the lever and all of the post except for the pin. 

I agree with the approach suggested by Theo - don't use ant glue but a sliver of hard wood inserted into the hole, then try pushing in the post using a tool like that suggested by Theo.

I keep a supply of ice lolly (popsicle for our non-UK brethren) sticks - these are usually made of beech and are easily obtained. 

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If you use a sliver of wood, you can risk displacing the lever away from it's correct position and ending up with either the pad not concentric to the hole, or the button axis out of line with the axis of the peg hole and the bushed key hole in the finger plate. This can still happen whatever technique you use, but packing the hole is probably the riskiest technique.

 

I use either super glue gel, or I crimp the pivot post tang across its corners to displace the brass, making it jagged to it keys into the wood better. or may be crimping and a spot of glue.

 

Dave

 

 

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