Tuning concertina reed.

[MashedCarrots]

I tried tuning a concertina reed .

https://youtu.be/sUidJsFjTCA

 

I'd appreciate if you instruct me that if there is an error in my understanding of it.

[Richard Mellish]

I'm reminded of the barber shop scene in one of the Marx Brothers' films: a bit too much off one side, so then take a bit off the other side, but then that's too short so take a bit more of the first side, etc. Surely one should file very little to start with, then a bit more if necessary. Also what about the effect of the reed chamber on pitch?

[MashedCarrots]

Thank you for your advice.

Reed chamber on pitch was 5~10 cent higher than correct pitch.

[wes williams]

That isn't a good example of how to tune a reed. Most folks here would support the reed by placing a shim of some kind (eg old style double sided razor blade or feeler gauge) between the shoe and the reed unfixed end when filing. That way filing is much more precise and the file need never touch the shoe.

[Sprunghub]

That is a very pretty tuning rig, but a fairly ugly application.

 

Ebay sells 'shim steel' you can get small sheets for no money which will create a very thin support for the reed which will slide almost down to the fixing point.  With the shim beneath it will elevate the reed tongue slightly, even for the belly/low filing.  It also allows you to 'fine' file the side of the reed at the filed point which may have some displaced steel  from the abrading which can snag the aperture.

 

Filing the belly, to lower pitch - even supported - allows (causes ?)  the tongue to drop at the tip so I found an almost invariable need to tweak the tip out and reformat the curve to bring the up. 

 

The other thing to weigh up is that if it is 5 - 10 high "in" the instrument......it will potentially be a different 'score' outside, ie. on the tuning jig, so there is an ongoing calculus for each reed of the difference "inside" and outside the 'Tina.  My finishing is done with the reed back in the 'box' with the end clamped under hand pressure, other end between the thigh's ie. without bolts in place just to assess the one note.  Personally I found the note 'deflection' inside and outside, to be pretty standard which meant that I could apply a standard differential.

 

There are posts from people who know on how those differentials apply.  

 

 

 

[Greg Jowaisas]

Yikes!  Please stop and get the Dave Elliott book.  This is not a good way to file a reed.

 

"Scratching" at right angles to the length of the reed is an invitation for tongue failure.  (Although thankfully it appears you were using a light touch.)

 

Best to practice your file technique on some metal material other than a concertina reed you intend to use.  Like any tool, using a file efficiently and without "destructive affect" takes practice.  Practice getting a smooth, even cut all the way across a piece of material with the flat of the file.  Practice with a material that has similar dimensions to the width of a reed.  (It is very easy to inadvertently tip file and file more toward one edge rather than flat all the way across.  It takes PRACTICE to get a feel for doing this correctly.  Keep monitoring and looking at your work as you practice to make sure the file is not tilting.  The cut should be at a 45 degree angle to the length of the reed/material.  (Hopefully other reeds in the instrument have the proper orientation of file marks.)

 

As advised, use a shim (feeler gauge type thickness) under the reed tongue  for support and to protect the reed frame.

 

You can quickly compromise or ruin a reed with poor filing.  Only after you can reliably control the file on practice material should you attempt an actual reed.  (And even then you are always checking the file marks to make sure of the cut.)

 

If in doubt, stop, and seek professional help.