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#91 David Hornett

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Posted 07 June 2014 - 03:03 AM

Reed labelled C# (tongue scavenged for the Jeffries) length 36.96 / 35.51, width at heel (where no deburring evident) = 3.13 / 325. I doubt this will help, the heel is not vertical at the end of the slot, it actually slopes forward. At the toe it is undercut about 3/4 of the way up (it is easy to see where it stops). The slot at the toe and heel is not at right angles to the side, but I cannot tell how crooked they are as the calliper's jaws will not measure right to the corners (the thickness of the jaws holds them from the side. The sides are sloped, but the deburring rounds the edges: these measurements are as accurate as I can get them, but really hardly accurate.

 

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#92 Terry McGee

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Posted 07 June 2014 - 08:13 AM

Hmmm, sounds like a bit of a challenge to quantify without a specialist setup.  It would be nice though to have something to say.  What about a description?  If you were to look at a bass reed, a midrange reed and a top reed, could you describe the varying nature of the treatments given to the four sides of the reed slots? E.G:

 

C3

Heel:  blah

Sides: blah

Tip: blah

 

where blah might be something like "mildly slopes outwards from about 3/4 of the way up, bottom edge deburred (or chamfered? or rounded?)"

 

I'm assuming in the above that bass, middle and top might be the appropriate divisions.  You might find that there are four divisions, or just two.  You might also look to see if the divisions fade into each other as a continuum, or snap into each other as tiers.  If you can locate the crossover points between divisions, all the better.

 

Don't worry.  Pretty soon you'll be able to go back to your family..... 

 

Terry



#93 Terry McGee

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Posted 07 June 2014 - 06:26 PM

 

"All three of you"?  Gulp.  You mean..... we're not alone?


Though I don't have much to contribute, I am following the thread with interest. :)

 

 

Eeek!  A stalker!

 

Well, as you've no doubt noticed, we're making this stuff up as we're going along, so do feel free to chip in, innocent bystanders.  For example, if the task is to document the reeds used in this particular instrument, have we done enough?  Do we need to consider any other measurements or observations?  Are we interested in say, the length of the reed shoe?  Or its width?  Do those things tell us anything useful?

 

And if so, how do we best define the width?  Width across the blunt end and a diameter for the rounded end?  Or is width across the blunt end enough, as the included angle of the long sides is a given?  (If it is a given, someone here can probably give it!)

 

As David said, we've learned a lot about reeds in this project.  Speaking for myself, I've gone from total ignorance to an advanced state of ignorance in only a week!  

 

Terry



#94 Terry McGee

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Posted 07 June 2014 - 07:14 PM

It struck me that it would be instructive to be able to view the reed thickness, width and length all on one graph, as these all contribute to the reed's tuning.  Width and length are not incremental - they are, for practical purposes, varied in tiers.  But thickness is infinitely variable (within the limits of stock thickness!) and so it must fall to thickness to make up for the rigidities of the other two parameters.  So we should be particularly interested in what happens at the changeover points.  

 

Trying to display so much data on one graph presents problems, so my first attempt simply assigns fake values to width and length.  But it does enable us to see where the changes are happening, which is our main aim. Keep in mind these are not to scale; indeed I've managed their values to maximise clarity.  It's their location and direction that we're interested in.

 

Lachenal Duet 8816 Reed Thickness 2D with length and width indication.gif

 

You'll see the new information, as the two lowest traces on the graph.  Sure enough, looking up from any of these changes we can usually see sudden jerks in one or more of the thickness curves, as the reed tuner deftly swerves to avoid an oncoming tuning issue.  The laws of physics seem still to be working....

 

Note though, the biggest cat among the pigeons remains the sudden 41% reduction in stock thickness, which we dealt with earlier.  Had the concertina continued to exist, it would have been interesting to compare the sounds of the two reeds on each side of that change.  (That might still be possible on the tuning table?)  It's a big change to ask the reed tuner to deal with.

 

Terry



#95 alex_holden

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Posted 08 June 2014 - 01:50 AM

OK. It has occurred to me that we're ignoring a variable: the stiffness of the steel used. This would vary depending on the exact alloy used (the percentage of carbon and other elements), how it was heat-treated, and it might even change during profiling and when the reed is played because of the work hardening effect. Before modern production techniques the alloy and heat treatment would have varied over a wider range than modern mass-produced stuff. That's not to say it was poorer quality, but it may have required some kind of sorting and selection process if you wanted to get consistent results. (On a side note, historically Swedish steel was reputedly 'better' than British steel because it was produced using charcoal rather than coke, which led to a lower sulphur content - the truth of this is somewhat debatable). Unfortunately I can't think of a non-destructive way to measure the stiffness of the steel used to make an existing reed!

Do we even know if all the tongues in a given instrument were made from the exact same steel? Might there be some advantage to, for example, deliberately using a more or less stiff material for the reeds in a particular range of pitches?

#96 Terry McGee

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Posted 08 June 2014 - 03:49 AM

Are you telling us you don't have an X-Ray Fluorescence Spectrometer at home?  (I think I must have lent mine to a friend.)

 

If we could find someone with access to a mass spectrometer, we wouldn't need much material.  Filing a bit from behind the clamp would probably do it.

 

In one of my many previous lives I built electronics for mass spectrometers.  I was part of the small team who had to handwind two trapezoidal coils with 10,000 turns of enamelled wire each for detecting flux change in the steering magnet of the MS2 at Earth Sciences.  We couldn't afford one shorted turn, which is why handwinding.  It took us weeks!

 

Interestingly, David snitched a reed from this collection to replace a broken one in his Jeffries, but reports he couldn't detect any difference in workability or sound between the adjacent reeds.  But maybe others have had different experiences?

 

Terry



#97 Greg Jowaisas

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Posted 08 June 2014 - 05:40 AM

Alex brings up a very good point regarding the qualities of the steel used for reed tongues.  I've tuned over 500 concertinas and some noticeable patterns have occurred to me.

 

Most Lachenal steel is softer (files easier) and sets (bends) fairly easy.  (Occasionally I've tuned a Lachenal with a set of reeds that have exceptionally hard steel with great resiliency)

 

Wheatstone steel is generally harder than Lachenal (takes more passes with the file to effect the same change) and generally takes more effort to set (bend)

 

Jeffries instruments (I've tuned 30-40 as my sample size) generally have steel about as hard as Wheatstone.  However in some Jeffries instruments I've encountered  tongue steel that is harder to set (bend)  This includes reeds that have come to me exceptionally thin but seem to be especially resilient (very scary and sometimes frustrating to have to bend them so far to change the set)  Anecdotally, I don't believe that steel was significantly harder to file.

 

I'm not a metallurgist so perhaps someone else can explain if apparent hardness and resiliency are related or independent.  It does seem to me that resilience or "springiness" would be a factor in making a reed's successful profile.

 

A bit off topic, but I've often wondered if the differences in steel contributes to the characteristics of sound in different makers' instruments.  (That Lachenal "fruity sound" as opposed to the even, "business-like tone" of a Wheatstone)  Concertinas have so many variables: metal vs. wood ends; types of wood; tightness of slots; hardness of reed pan wood; open area of fretwork; valve thickness and on and on.  The old saw is that "If you stick a Lachenal reed in a Jeffries, it will sound like a Jeffries", and to a certain extent that is true.  But a careful listener can sometimes pick out the "cuckoos hiding in the nest".  I'm not sure how much of the give away is always in the response, volume or tone.

 

Greg

 


Edited by Greg Jowaisas, 08 June 2014 - 05:42 AM.


#98 blue eyed sailor

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Posted 08 June 2014 - 06:18 AM

Lachenal "fruity sound" as opposed to the even, "business-like tone" of a Wheatstone...

 

I guess a characterisation every afficionado (or afficionada) of his (or her) Edeo, Excelsior a.s.f. will gladly second... :)

 

P.S.: Even more OT; That very concept of "fruitiness" occurred to me once before from Paul McCartney talking about his, well, clarinatty Beatles songs...  B) 



#99 Terry McGee

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Posted 08 June 2014 - 07:31 AM

Thanks for those observations, Greg.  I imagine that reed steel has a lot in common with music wire (a.k.a. piano wire).  Hard, but not brittle; high yield strength.  

 

Spark testing is a very simple test for steels if you have a grinder (and a few sacrificial reeds you don't mind grinding!).  There's a useful introduction at: http://en.wikipedia....i/Spark_testing.  I just tried some very good German piano wire - I'd say it conformed to medium-to-high-carbon (pronounced forking directly from the wheel, the biggest brightest yellow sparks at the end of the forks).

 

You can file piano wire too, unlike the really high carbon tool steels over which the file simply skates.  Piano wire resists bending (high yield strength) but can be bent, again unlike higher carbon steels that will crack.  

 

 

 

A bit off topic, but I've often wondered if the differences in steel contributes to the characteristics of sound in different makers' instruments.  (That Lachenal "fruity sound" as opposed to the even, "business-like tone" of a Wheatstone)  Concertinas have so many variables: metal vs. wood ends; types of wood; tightness of slots; hardness of reed pan wood; open area of fretwork; valve thickness and on and on.  The old saw is that "If you stick a Lachenal reed in a Jeffries, it will sound like a Jeffries", and to a certain extent that is true.  But a careful listener can sometimes pick out the "cuckoos hiding in the nest".  I'm not sure how much of the give away is always in the response, volume or tone.

 

If anyone is in the position of being able to supply samples of "fruity" and "business-like" tones (ideally made under the same conditions with the same recording setup), I'll be happy to analyse them to see if there are any clues in the sounds themselves.

 

Terry



#100 alex_holden

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Posted 08 June 2014 - 09:46 AM

It was probably a high carbon spring steel, much like the stuff that clockmakers used for centuries in mainsprings, though the final characteristics depend to a large extent upon the hardening and tempering process. BTW you can file recycled old file steel (known to blacksmiths as OFS) if you anneal it in the forge first.

Very interesting about Lachenal reeds being softer; perhaps they used a lower carbon steel to reduce the time their workers spent on profiling and make their files last longer (good fine-tooth files were extremely labour intensive to make because the teeth had to be cut by hand with a fine chisel!). Presumably Wheatstone and Jeffries had good reasons for using harder steel despite it being more difficult to work. Is it generally accepted that they have a 'better' tone or are louder or stay in tune longer or break less often?

#101 Chris Ghent

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Posted 08 June 2014 - 07:02 PM

About ten years ago Richard Evans and I sent a number of reeds for hardness testing. Just from memory there were two Lach reeds, two Jeffries, two Wheatstone. The hardest was a Wheatstone but the other Wheatstone was relatively soft. One of the Lachenals was quite hard though not as hard as the hard Wheatstone, the other was soft. Both Jeffries were relatively hard. Having said that, the role of hardness in a reed is not well understood by me.

The difference in tone between vintage brands is better explained by wood choice and design, and by the clearance in the reed/frame gap, than by steel composition. I suspect given all other factors being the same, all relatively hard steels would produce much the same sound. Steel choice might contribute to response however. Brass produces a different sound but this can be explained in terms of stiffness and tip speed.

I suspect duplicates of old steels would be hard to find. Two factors were at work. 1) all subterranean ore bodies are different in their composition. 2) The big cost in steel production can be finding an economical way of bringing coal and iron ore together. The spot on the Severn River where both coal and iron were found in the same cliff face substantially kicked along the industrial revolution. A child of this equation is that early industry tended to use only one ore source, hence a steel factory could be putting out a unique product. Today ores are blended to create many different alloys.

It is hard to imagine Jeffries used Swedish steel for no real reason. It must have been cheaper, or made a better reed (in his opinion) or created a PR opportunity ("reeds made from finest Swedish steel!"). This last would be easy to disprove if period advertisements were available.

Spotting a Lach reed in a Jeffries can be difficult because the steady state sound comes from the wood and the design. The clues are in the response and whether the reed generates more upper partials from a close reed/frame gap. The effect of upper partials on our ear is different to lower ones. The combinations of lower ones contain much of the character we recognise as "fruity" or "nasal". I feel tempted to describe upper partials in terms such as edginess, cut, or annoying buzz. If the concertina is designed to have a lot of upper partial absorption then this difference may be hard to hear but you will feel it.

I find a file lasts about 1.5 concertinas, so 90 reeds. After that it is blunt and you have to use too much force. I always know when I held off too long before changing files; the first reed with the new file becomes quickly too thin and has to be discarded.

Thanks for your experiences Greg, I share your wondering how much crossover there is between hardness and resilience. I use the word stiffness for resilience. Every time I have ventured into this area it has become very complicated very quickly and I retreat in favour of more immediate progress. (Any moment now someone is going to use the term 'Young's modulus of elasticity'. http://en.wikipedia....Young's_modulus )

Sorry I became discursive, off now, I have wood to split and reeds to make.

#102 alex_holden

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Posted 09 June 2014 - 01:35 AM

I held off on mentioning Young's Modulus of elasticity because I'm a bit fuzzy on the details myself. From what I've just read it only varies by a small amount with the carbon content and heat treatment of the steel. It does vary with temperature, though perhaps not enough to matter in our application.

Yield strength is a different property, which does vary with the carbon content and heat treatment of the steel. Those reeds that Greg found took more force to change the set of will have had a higher yield strength. Harder materials have a greater yield strength. I would imagine that a reed with a higher yield strength might be less likely to lose its set over time; the disadvantage though of increasing the hardness is that also makes the material more brittle and hence more likely to break.

#103 alex_holden

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Posted 09 June 2014 - 01:51 AM

It is hard to imagine Jeffries used Swedish steel for no real reason. It must have been cheaper, or made a better reed (in his opinion) or created a PR opportunity ("reeds made from finest Swedish steel!"). This last would be easy to disprove if period advertisements were available.


I'm pretty sure Swedish steel was more expensive in Britain; it was used in some applications because it was regarded as better quality than the native stuff. For the small quantity that went into a concertina, it may have been worth the extra cost just to be able to say to customers they were using the best available materials (regardless of whether there really was any detectable difference).

I find a file lasts about 1.5 concertinas, so 90 reeds. After that it is blunt and you have to use too much force. I always know when I held off too long before changing files; the first reed with the new file becomes quickly too thin and has to be discarded.


If the Victorian reed profilers were wearing out files that quickly it must have been quite a significant expense. I wonder whether the files were supplied to outworkers by the company or if the workers had to buy them out of the payment received for completed work.

#104 Dana Johnson

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Posted 09 June 2014 - 10:56 PM

OK. It has occurred to me that we're ignoring a variable: the stiffness of the steel used. This would vary depending on the exact alloy used (the percentage of carbon and other elements), how it was heat-treated, and it might even change during profiling and when the reed is played because of the work hardening effect. Before modern production techniques the alloy and heat treatment would have varied over a wider range than modern mass-produced stuff. That's not to say it was poorer quality, but it may have required some kind of sorting and selection process if you wanted to get consistent results. (On a side note, historically Swedish steel was reputedly 'better' than British steel because it was produced using charcoal rather than coke, which led to a lower sulphur content - the truth of this is somewhat debatable). Unfortunately I can't think of a non-destructive way to measure the stiffness of the steel used to make an existing reed!Do we even know if all the tongues in a given instrument were made from the exact same steel? Might there be some advantage to, for example, deliberately using a more or less stiff material for the reeds in a particular range of pitches?


Individual alloys do vary In Stiffness (modulus of elasticity ). For steels, the variation is less than you might think. Hardness and stiffness are not the same thing. You can dramatically vary the temper of a given piece of reed steel without affecting it's stiffness. You can affect the amount of bending it will take before it snaps or stays bent, but it will maintain pitch as long as it isn't pushed into vibrating past it's elastic limit. As far as non destructive measuring goes, take two samples of identical dimensions apply an identical load and measure the deflection. Reeds make a good sample. I started making reeds from 1095 spring steel and later switched to a more complex alloy provided as "reed" steel ( but for reed valves, not concertinas ) it is a harder temper and holds it's set better. It also shears without tending to form microscopic cracks, which is a boon. Even though it has a number of other alloying ingredients in it but similar carbon content, the stiffness is almost identical to the 1095 carbon steel. There is little difference in stiffness even as the carbon content drops well below medium carbon level or even with stainless, chrome or chrome moly steels going from about 27,000,000 psi to 30,000,000 psi for most steels with the majority of them hovering around 29,000,000 psi.
Changing to brass or other materials makes a big difference. Advantages between English or Swedish steels has to come frome some other property. Any variation in steel stiffness would be overwhelmed by profile variations in concertina reeds.
Dana

#105 Terry McGee

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Posted 19 June 2014 - 03:28 AM

Now, this has been such a ramble, I thought it would be good to pull together a more concise version of the final results.  But also to include a bit of background, like why on earth David embarked on this journey in the first place.  You'll find it at http://www.mcgee-flu... 3316 reeds.htm.

 

I have avoided including comments from others than David and me, but directed readers here if they want more.  

 

If you spot any howlers, let me know!

 

Terry



#106 alex_holden

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Posted 19 June 2014 - 06:12 AM

Loads of useful information there. Thank you Terry and David! :)

#107 malcolm clapp

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Posted 19 June 2014 - 08:15 AM

David and Terry, I have sent  PMs.



#108 Terry McGee

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Posted 19 June 2014 - 06:20 PM

Loads of useful information there. Thank you Terry and David! :)

 

Thanks Alex.  

 

We do have to keep in mind a point which I think Chris alluded to previously - that this is one set of reeds for one make and one type of concertina made on one day by one man in a hurry.  We shouldn't view it as indicative of the broad range of concertinas out there.  It may well be, but we can't tell from here.

 

It would be great to have a "bank" of this kind of information, covering at least the major makers and models, and ideally covering their best periods.  (Their worst might be more fun!)  I'm happy to help anyone who has or could take a set of data to present it visually.  Even a partial data set is better than none.

 

David's insistence on avoiding reeds that might have been retuned makes a lot of sense in this regard.  Reeds at high pitch will have to have been flattened, which requires work on the bellies. Depending on the skill and care taken by the tuner, that could either alter the profile quite a bit at one point, or just alter it a little over a wider region. It would be interesting to see some measurements before and after to know how subtly this can be done.

 

Terry






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