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#37 Terry McGee

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Posted 07 April 2014 - 05:27 PM

Now, is it possible that the 45º scratches were made by a grinding process, with the wheel shaped and set at that angle to produce a wide shallow round-edged trough?

 

Having said that though, it's good to remember that handfiling was taught as a serious skill in days gone by.  I remember my friends who went into "fitting and machining" (even the title gives equal weight to handwork) had to produce a 1" steel cube entirely by handfiling, and it had to meet very strict criteria for squareness and flatness.  Even we in electronics were given some filing training.  

 

The chappie in the Pathe film would have got into trouble with the teacher - he is filing back and forward, rather than lifting his file on the return stroke.  Back and forth is good on copper, silver and other cheesey metals - it helps clear the teeth for the next forward stroke.  But on hard steel like reeds, it rounds and wears the teeth.

 

Terry



#38 Chris Ghent

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Posted 07 April 2014 - 10:04 PM

It is extremely hard to file reeds when lifting the file between strokes, I did that at first, mindful of warnings backfiling would ruin the file.

David, if you are getting all of that info, note the widths as well so you can see the taper.

What is the filing pattern beside the clamp, do the witness marks swing around to 90°? If there was to be a form you would need to come up with a material the form could be made of. If it was softer than the file then it would need to be remade after every reed. If it was harder than the file then you would need to replace the file all the time, unlikely given the way they were made and the likely cost. The only "form" method I can imagine is a surface grinder running on a template in the manner of a pantograph. Not impossible but I think you cannot underestimate the skill of a man with a file. Terry mentioned filing exercises for apprentices, Richard Evans tells me one of his was he had to create a cube exactly 1"square which would pass through a square hole in a 1" plate in any orientation with no more than 1 thousandth of an inch clearance.

#39 Chris Ghent

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Posted 07 April 2014 - 10:05 PM

A rooster?


Sorry, local vernacular leaked through, not pejorative...

#40 alex_holden

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Posted 08 April 2014 - 12:52 AM

Terry mentioned filing exercises for apprentices, Richard Evans tells me one of his was he had to create a cube exactly 1"square which would pass through a square hole in a 1" plate in any orientation with no more than 1 thousandth of an inch clearance.


My dad learned the same exercise as an engineering apprentice at Lucas Aerospace in the 1960s.

#41 alex_holden

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Posted 08 April 2014 - 12:58 AM

A rooster?

Sorry, local vernacular leaked through, not pejorative...


I was curious as to what it meant. This 'rooster' is planning to sell a range of cast brass concertina reed frames?

#42 Chris Ghent

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Posted 08 April 2014 - 04:51 AM

I am not clear on his plans. He has told me he isn't intending to make whole concertinas, just reed assmblies. His progress so far is slow but fairly solid. I have seen an example of the frames (he has a large number of sizes) and they look very valid to me. I understand they are not very expensive to produce. While  I would not be using them myself as I have an in-house solution, the important thing for me would be repeatability, yet to be proven. Nevertheless I can imagine much interest from one-off builders at the least or from builders wanting to move from accordion reeds to a trad reed.The frame I saw would be a much better start than the CZ assemblies which have the geometry of an accordeon reed in a single bevelled riveted brass frame. The examples I saw had erratic clearances.  Good reed assemblies need good frames, you could make a bad reed assembly with a good frame but you will not make a good assembly with a bad frame.



#43 David Hornett

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Posted 08 April 2014 - 06:35 AM

Well, I will, when I get the pin micrometer, now measure for each reed:

 

width at tip

Width at heel

heel thickness under strap

length

5 point thickness

shoe thickness

 

and then I will go to the National Folk Festival in Canberra, play my accordian and whistles and forget all this nonsense for a time.

 

As for a form: with the big reeds where a lot of meat needs to be removed, yet still allow min of .025mm in the belly, they could easily be laid over a shape (form) and filed flat at 45%, and for someone who could hold a file steady it would be a quick task to make a few passes and then let the reed spring back, hey presto, and exactly the same profile for each reed. The file would not even graze the shape, those old fellow could shave a 1" cube to within a 1000 thou of an inch, I believe. Anyway, once there was a steel template of the desired shape as many copies as one liked could be poured from pewter for instance: I am going to give it a go and see.

 

By the way, the .04 cut at the heel is about 5% off parallel with the mounting plate, and it does appear as though the file has been moved much more lightly over this section, for whatever reason.

 

If all fails, there is one sure thing, in a few weeks I will be a much wiser man than I am now



#44 Terry McGee

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Posted 08 April 2014 - 07:00 AM

When we lived in Canberra, I would camp at the National (to avoid driving at the end of a long night's sessioning).  So, what to do in the mornings before the sessions got going again?  I'd set up on one of the tables under the trees outside the Restaurant venue and measure flutes from my collection.  People would wander up and chat and we might break into a few tunes from time to time.  Indeed, this image from my website is taken there:

 

Terry.gif

It became known as Terry's Office.  Feel free to use it to measure reeds if there's a dull morning....

 

Heh heh, note the heavy jumper.  Every year I'd go, forgetting that Canberra can be a bit chilly camping at Easter.  On the second day I'd have to buy a new jumper from one of the stall holders.  Now we've moved down the coast, I have a cupboard full of jumpers and no need for them.

 

Terry



#45 Chris Ghent

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Posted 08 April 2014 - 09:31 AM

By the way, the .04 cut at the heel is about 5% off parallel with the mounting plate, and it does appear as though the file has been moved much more lightly over this section, for whatever reason.

I take this as evidence the reed was hand filed in free form...

If all fails, there is one sure thing, in a few weeks I will be a much wiser man than I am now

Guaranteed...

#46 Terry McGee

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Posted 08 April 2014 - 05:22 PM

 

And another question.  The Lachenal I've been looking at has remanent signs of deep pitting on parts of the reeds, which generally have been polished up.  Clearly the reeds were very rusty until recently.  Now, cleaning off most of deep pitting on both sides will require removing quite a bit of metal.  Then tuning the instrument will mean removing more.  Obviously, the profiling can never again be the same as the maker intended.  The reeds will be more flexible (thinner in the waist) but also lighter (thinner at the tip).  What would we expect that to do?  Make the instrument play on less bellow pressure, but run into problems at higher bellow pressures?  
 
Terry

I think I would not remove the pitting. Just fix the actual problems, that is, if it is out of tune, tune it. They don't have to look good to work well. Thinning the reeds could change the playing characteristics but it is all relative. How much would you be removing?

 

 

Sorry, missed this response.  I'm not doing the rust removal, that's already been done by someone previously.  Impossible to know how much metal they removed (without having access to the kind of data David is collecting at the moment - we need that kind of data in a public place for precisely this reason), excepting to note that the reeds are mostly shiny, but there are deep pockets of pitting they didn't remove.  That suggests to me they removed quite a lot, and that's a bit of a worry.

 

Terry



#47 Terry McGee

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Posted 08 April 2014 - 05:36 PM

David

 

When you get down to collecting your data, it would be good for you to enter it straight into a spreadsheet, rather than having the likes of me entering it later, thus doubling the risk of data error and misinterpretation.  

 

Are you comfortable with setting up spreadsheets or would you like me to set one up for you?  Based on the parameters you mention above?  Note range?

 

When I do this sort of stuff, I like to have the graphs working so I can see the developing picture.  It can alert you to measurement errors - if you see a bump where you think there shouldn't be a bump, you can retake the measurement.

 

Terry



#48 Terry McGee

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Posted 09 April 2014 - 02:03 AM

Oh, and one more thing.  Your plan was to collect 5 data points plus the heel thickness, 6 in all.  As Chris has pointed out sometime back, that's not really enough data to give the full picture.  We certainly saw a big improvement in understanding as we went from three points to five, so I'd be inclined to agree with him (despite my comprehensive ignorance!).  But you may not want to spend the rest of your life on the project (young people these days, I don't know!), and doing all the reeds to great depth is probably overkill.  But it certainly would be interesting to do some of the reeds (what would you think, Chris, one or two per octave?) to really high standard, to get the full picture.  It might be best to graph those separately, which I'm happy to do if that helps.  It might well be good to do that exercise first, as it will tell you how much data is needed per reed for the full story.

 

Terry



#49 David Hornett

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Posted 09 April 2014 - 02:07 AM

Ah ha, spread sheets, I once set up my finances on a spread sheet, very clever, totalled by itself, trotted out percentages and all. I returned to it a year or so later and guess what, for the life of me i could not remember how i'd done it all. if you could set up a spread sheet and email it would be great. I could read out the data and my son enter, would be a double check that way, in fact, if you set up three columns we could enter data for Lachenal, broad reed jones and Jeffries all for the same note. I even have a brass reed Crabb and a Wheatstone extended treble but these later instruments have been tuned. Duets of course have the same pitch push and pull so if there were two columns for each of them we may see an interesting difference but the same pitch! Beginning to look like a job for when I return from the National.

 

Crabb = standard three row

Jeffries 44 button duet

Lachenal 39 button duet

 

 

Notes to be measured C3 to A6:

 

width at tip

Width at heel

heel thickness under strap

internal slot length of shoe

5 point thickness

shoe thickness

Weighted or unweighted reeds

 

David



#50 Chris Ghent

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Posted 09 April 2014 - 09:58 AM

Doing every second reed would be adequate...

#51 Terry McGee

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Posted 09 April 2014 - 04:20 PM

Ah ha, spread sheets, I once set up my finances on a spread sheet, very clever, totalled by itself, trotted out percentages and all. I returned to it a year or so later and guess what, for the life of me i could not remember how i'd done it all. if you could set up a spread sheet and email it would be great. I could read out the data and my son enter, would be a double check that way, in fact, if you set up three columns we could enter data for Lachenal, broad reed jones and Jeffries all for the same note. I even have a brass reed Crabb and a Wheatstone extended treble but these later instruments have been tuned. Duets of course have the same pitch push and pull so if there were two columns for each of them we may see an interesting difference but the same pitch! Beginning to look like a job for when I return from the National.

 

Crabb = standard three row

Jeffries 44 button duet

Lachenal 39 button duet

 

 

Notes to be measured C3 to A6:

 

width at tip

Width at heel

heel thickness under strap

internal slot length of shoe

5 point thickness

shoe thickness

Weighted or unweighted reeds

 

David

 

OK, I'll give it a go.  Won't do three columns for the various instruments, as it would get too unwieldy.  I'll send you a template, and you can open it and Save As for each instrument.  Now, we'd better check you will be able to open it.   I'm running a PC so I can save as .XLS (Excel) format, or the Open Office .ods format.  Can you deal with one of those?

 

And shoot me an email to terry@mcgee-flutes.com so I can send it to you.

 

Terry



#52 David Hornett

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Posted 19 May 2014 - 01:46 AM

Terry,

 

I emailed the measurements yesterday. Have a look at them please and post if sense and sensibility can be had from the graphed figures, only 5 points plus the heel measured, and slot length, but they do seem to say something when all the data is considered together, and being a duet there are a lot in duplicate, triplet and indeed ... well whatever the word for 4 copies is. I hope people are still interested. The measurements were done twice over to minimise mistakes, and also to try and understand any anomalies.

 

David



#53 Wolf Molkentin

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Posted 19 May 2014 - 03:44 AM

quadruplet B)

#54 Terry McGee

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Posted 19 May 2014 - 06:28 AM

Terry,

 

I emailed the measurements yesterday. Have a look at them please and post if sense and sensibility can be had from the graphed figures, only 5 points plus the heel measured, and slot length, but they do seem to say something when all the data is considered together, and being a duet there are a lot in duplicate, triplet and indeed ... well whatever the word for 4 copies is. I hope people are still interested. The measurements were done twice over to minimise mistakes, and also to try and understand any anomalies.

 

David

 

Hi David

 

OK, I'll dig into them and see what it all yields.  Might take a day or two - just back from a routine maintenance of the National Carillon in Canberra - so I'm very sore and very tired.  

 

How instruments vary.  A concertina you hold on your knee.  A carillon you have to be careful not to fall off as you'd kill yourself for sure.  Certainly, at 40 tonnes, you wouldn't want to hold it on your knee. 

 

Terry






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