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Hammering Reed Frames ?


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A man who restores old accordeons says he has succesfully improved reeds by hammering them... I think he means gently beating the frames to close the air gap between tongue and slot. 'Hammer and Chissel' is how he put it.

 

Now I know that better reeds have closer tolerances but has anyone here heard of this practice?

 

I doubt it could be applied to concertina reeds but... who knows!

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Maybe he means hammering the rivets holding accordion (and indeed some concertina) reeds to the frames? They can sometimes be a bit loose in old instruments.

 

Off topic, but I have heard a few old time tuners in Oz referring to "stroking" the reeds, which I interpret to mean using an abrasive material to flatten/sharpen the pitch.

 

Perhaps we need a wee booklet on nomenclature of the parts and repair terminology of accordions, Geoff.... :wacko: :wacko: :wacko:

 

 

 

Edited to correct spelling of nomenclature (I think....)

Edited by malcolm clapp
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The reference to a chisel makes me wonder if perhaps he's peening the top surface of the frame next to the opening to close it up slightly. I can see it potentially working if you have a delicate touch (and if you go a smidgen too far and it starts buzzing/sticking, take a whisker off with a fine file).

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A friend who has visited Castefidardo on a number of occasions tells me he has seen people peening the top of accordion reeds to close the reed/frame gap. I had a go at it on a Lachenal reed and could not find a way to make it an orderly process. It leaves what engineers call witness marks and is hard to do consistently. Better to replace the tongue. Mind you, soft aluminium as used in accordion frames would be a better medium for it than brass, which work hardens.

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A friend who has visited Castefidardo on a number of occasions tells me he has seen people peening the top of accordion reeds to close the reed/frame gap. I had a go at it on a Lachenal reed and could not find a way to make it an orderly process. It leaves what engineers call witness marks and is hard to do consistently. Better to replace the tongue. Mind you, soft aluminium as used in accordion frames would be a better medium for it than brass, which work hardens.

 

Edited to remove content as obviously not relevant.

 

Geoffrey.

Edited by Geoffrey Crabb
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Striking Improvements... perhaps ? ;)

 

 

I think my informant was refering to "peening" the top surface of the frame to spread the metal and close the slot a wee bit. Maybe it does not matter if the slot sides are somewhat uneven ,or less straight that they were originally, but that some of the air gap is reduced ?

Edited by Geoff Wooff
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Harmonica technicians/customisers sometimes use a technique that they call "embossing" to close the reed slot, though it's more of a burnishing process that doesn't involve the use of anything as heavy-duty as a hammer and chisel. But in a Harmonica World article Rick Epping (who invented embossing) goes on to describe the accordion process (complete with photos of a "coined" reedplate), which might be achieved with those tools:

 

A few years later I learned that the process which was sometimes used on accordion reeds is very different. Instead of embossing, or burnishing the upper reed slot edge, a narrow line is stamped, or coined onto the upper surface of the reed frame, a short distance away from the slot’s edge.

 

As with reed slot embossing, reed plate coining results in a decrease in reed-to-slot tolerance, except that, while embossing only narrows the slot at the surface, coining results in the reed slot being narrowed through a greater depth of the reed plate, with the slot’s edges remaining untouched.

 

Whilst the Italian reed maker appears to be using his hammer to tighten the rivets, then to true-up the reedplate where it has
become distorted in the rivetting process.

Edited by Stephen Chambers
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Rick has also written this about the embossing, or coining, of accordion reeds:

 

The main problem I can see in employing slot embossing on accordion reeds isthat embossing effectively lowers the slot edge into the reed slot, creatinga vertical gap between the reed and slot which requires the reed to berecessed into the slot at the rivet pad in order to compensate.  This iseasy enough to do with harmonica reeds; factory workers sometimes use theirfingernail to lower the reed at the rivet pad when adjusting newly rivetedreeds and this how I adjust reeds after embossing.  Accordion reeds arethicker and much harder, being made of blue steel, and cannot easily beadjusted in this manner.  Coining an area of the reed plate offset from thereed slot can achieve similar results to embossing without lowering the reedslot edge.  I've attempted coining harmonica reed plates but found that theycan become deformed enough to cause air leakage between the reed plate andcomb.  Accordion reed plates are thicker and less likely to deform aftercoining and, anyway, are set onto their reed blocks with wax so that anyirregularities or gaps between are filled.  However, I doubt that anytechnique like this was ever very widespread as I only ever saw it on a fewold Hohner accordions, made during the period that the Italian masteraccordion maker Giovanni Gola was in charge of Hohner's accordionproduction.  My guess is that this was a technique that Gola had used in thepast and for a period incorporated into Hohner accordion production. Accordion reed slots, even for high-quality handmade reeds, are stamped outon heavy presses.  After stamping, enough of the surface of the reed plateis then milled away to eliminate any material deformation around the toolentry area and create an even, sharp slot edge.
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Whilst the Italian reed maker appears to be using his hammer to tighten the rivets, then to true-up the reedplate where it has

become distorted in the rivetting process.

While it is hard to see exactly what he is doing because it is often behind his hand and he moves very fast, my recollection is he gives the reed frames (can't remember the word accordion people use for their reed assemblies, has to be old timer's setting in) a few nice cracks on the side which would serve the same purpose as peening the top.

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  • 2 weeks later...

Going right back to the beginning: why would you want to do this? The reed plate is not a wearing surface, so how is it changing its dimensions? I have no experience of working with reeds, but as a clockmaker, I regularly find pivot holes (the bearing surfaces in clock plates, which are wearing surfaces) closed up by a series of punch marks around the hole, which is then broached back to a good fit to avoid having to rebush the plate (which is the correct solution to wear). It is generally recognised as a form of vandalism! I can't work out why anyone would want to do this, but I may well have missed something.

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One measure of a good reed is a tight clearance between reed and frame. If this has not been achieved in the fitting process then it is a possiblility the metal can be stretched to close the gap. It is known to be done with accordion reeds. Nobody is suggesting this as a serious production method with concertina reeds, (or at least I don't think so!), just riffing on whether it is practical, who has done it, how to do it etc.

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It's supposedly a way of improving reeds that were originally made with relatively large clearances (because it takes more time to make a tongue that only just clears the sides of the slot than one that is a relatively sloppy fit). A tighter fit gives you more efficiency and better response.

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It's supposedly a way of improving reeds that were originally made with relatively large clearances (because it takes more time to make a tongue that only just clears the sides of the slot than one that is a relatively sloppy fit). A tighter fit gives you more efficiency and better response.

 

Sounds to me like a cheap way to somewhat improve reeds of lesser quality (i.e., relatively large clearance), but unlikely to bring them to the standard of reeds originally made with much tighter clearance, because it would be extremely difficult to get a uniform clearance via hammering.

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