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Reed Tuning Work Bench


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So, my little Jabez Austin 32 button had very verdigris laden brass reeds and, even after cleaning at my clockmaker friend’s workshop, the tuning is ‘interesting’ with quite a few pairs of reeds being markedly different from each other.
I think I’ll put a bit about it over in “EC tuning mystery solved....I think”
 in a little while, as they go into tuning in great detail and are making me question my choices, but here I’ll put up the Tuning workspace I’ve made. This will be put up in 8 chunks to keep text with relevant photos. I watched the Pathé Concertina Factory video ( https://youtu.be/4LFBNlildjA?si=LxwTHK84urWPVDrp) and decided to make a reed tester like theirs. Instead of a second master reed, I’m using the Pano Tuner app.

 I tracked down a paper bellows tutorial (https://www.instructables.com/Paper-Camera-Bellows/) though I put the seam line half way along one side, not at the corner. I also had the paper for the bellows on top of two more sheets of paper, when laying out the fold lines, so that the Biro would put in creases for the folding stage.

 

Reed Tuning 1.jpg

Edited by Duncan Luddite
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This I then glued, top and bottom, to two pieces of 7mm ply, the top one having been drilled out for the main intake and the two exhaust ports (this board is a reject side from the hex. case I’m also making). Kangaroo leather was fitted as valves; this I later skived down to about half thickness.ReedTuning1a.thumb.jpg.46cea81e47c382e599b7565e4885741b.jpgReedTuning2.thumb.jpg.3dae68633fddd8a773248a1b4c015aba.jpg

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The reed ‘shoe’ has a 2mm slot running down the middle and a fine ‘roo leather valve underneath. To help support it I fitted a length of pig’s bristle, making use of the natural curve to support, but not fully close, the valve. The leather and bristles are excess from my past trade as a hand sewn bespoke shoemaker.
A suede frame was stuck to the bottom edge to help make a seal.

Reed Tuning 3.jpg

Edited by Duncan Luddite
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Using a couple of strips cut from a hardwood venetian blind, sanded down to the thickness of the reed block (to clear the screw block and allow in situ filing of the reed), I hold them in place with 4 button headed screws. This enables very easy adjustment of the fit of the reed block: slacken the screws (usually just the ones on one side), slip the reed in until it’s about half a cm back from the end of the air slot, push on the slats such that they are firmly against the sides of the reed block but also firmly down on the surface of the reed shoe, and tighten the screws back up. Push the reed forward to cover the air slot and make a tight fit between the slats.
I did centre the slats/air slot position after this photo :)

Later I also added card stops to go around the end of the ‘shoe’ to give consistent placement on the bellows.

 

Reed Tuning 4.jpg

Reed Tuning 5.jpg

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The weight of the lower bellows board means that it only has to be let go to have enough draw to sound the reed. This allows consistent performance tests between pairs of reeds for assessing whether they require the same air pressure to give comparable results, without unconscious changes in arm effort to get equal sound.
Particularly useful in picking up when a reed is struggling to voice; the bellows is starting to drop and there’s nothing happening, now a little more speed and there’s a note starting; verses the note kicking in strongly straight away.

 

Reed Tuning 6.jpg

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A slip of 0.005” brass sheet is slipped under the reed as support for all filing.
Remember: We’re only removing ‘fairy dust’ each time before checking the tone, and making sure there’s no tiny burrs over the edges which will catch and affect the tone etc.

 I stroke the end of a sharp graver along the edges to take this off. No pressure as I don’t want to remove base metal.
Having a desk lamp off to the side helps 'light up' the file marks to keep track where the file is working on the reed.

 

ReedTuning7.thumb.jpg.e35d1f57a5cffeb60f9794a673ce9430.jpg

Edited by Duncan Luddite
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Very cool. I've made a paper bellows like that before, and I found that the corners didn't hold up for very long. I expect you'll at least have to reinforce them at some point. But I love the compactness of it, and I suppose it's relatively easy to just fold a whole new bellows when the paper wears out. Nice work!

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