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Stevie D

Maintenance Manual Typo?

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Hi all, new to this forum and got a question about David Elliott's book. On page 14, in the troubleshooting charts the same cause is given for two different symtoms: Reed is fast to speak but muted, and Reed stalls on initial button press or if playing loudly. Both of these are listed as gap too small, but that can' be right, can it? Shouldn't the stalling reed be gap too big? I ask because this is the problem I am having with my Marcus and would like to open it up and have a look. Thanks, stevie

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The book is right. A low set reed will speak on the slightest breath of wind but will not achieve as high a volume, and if you give it a lot of pressure suddenly it will choke.

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Stevie,

 

thanks for buying the book!, even more thanks for actually reading it.

 

Chris's explanation is correct. If the reed gap is correct then the air flow will be sufficient to easily excite the reed and as pressure builds then the reed will vibrate with greater amplitude and increased the volume. A correctly gapped reed will not allow enough pressure to build so that the tongue is held open by the air flow/ pressure, thus stalling, and the reed will always spring back allowing vibration to commence/ continue.

 

Dave

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Thanks to both of you for your replies. Dave, That made me chuckle. I found your book to be a good read, even to a Yankee machinist such as myself. Ive gotten the reed "better" but not good enough, and after 50+ tries! I'm getting tired of taking this thing apart, I'm guessing the pro's have some sort of bench tester. Hmmmm...

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Stevie,

 

it is time to help you sort out the problem, but we have little to go on,so, data please!

 

Symptoms & condition under which experienced?

push or pull?

reed type (steel, brass. accordion??)

make of concertina?

Anglo, English, Duet?

Note Value & octave?

 

Don't worry:- we help Yankees too, even machinists.

 

cheers

 

Dave

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... I'm guessing the pro's have some sort of bench tester. Hmmmm...

 

Dead right Stevie, it's called a "tuning bellows" and you can see one in use (for tuning) in the wonderful Concertina Factory Pathé newsreel (at 1.35, preceded by some machinery that you might appreciate - that reed-slot cutter is believed to have been made by Louis Lachenal and was revolutionary in 1848, since the slots were otherwise cut by hand).

 

The theoretical gap setting is usually said to be the thickness of the tip of the reed, though I'd find it often needs to be slightly more than that, but you'd want to make sure that the reed tongue is also correctly aligned in its slot. The tool for doing this work (and for slipping under the reed for tuning) is traditionally called a "lifter" and the one I'm using at the moment started life as a 3" x 1/2" .013 feeler gauge, but you could use a similar length of steel shim, of around that thickness.

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Dead right Stevie, it's called a "tuning bellows" and you can see one in use (for tuning) in the wonderful Concertina Factory Pathé newsreel (at 1.35, preceded by some machinery that you might appreciate - that reed-slot cutter is believed to have been made by Louis Lachenal and was revolutionary in 1848, since the slots were otherwise cut by hand).

 

Fantastic video, thanks! Was that the Crabb factory?

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... the wonderful Concertina Factory Pathé newsreel ...

 

Fantastic video, thanks! Was that the Crabb factory?

 

 

No, Wheatstone's, when they were at Duncan Terrace, Islington, sharing a Georgian house with the flute makers Rudall Carte's. Crabb's never had so much machinery, or as many staff, and the way Harry made reeds was incredibly laborious in comparison.

 

It was pretty much of a "swan song" for Wheatstone's, who were about to lose any semblance of autonomy and be swallowed-up into the large Boosey & Hawkes concern/factory at Edgware.

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