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Dave Leggett

BELLOWS CARDS (Is there an elephant in the room?)

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I was introduced to the rudiments of bellows-making some years ago by a well-established maker of 'the old school', who followed tradition, using bellows-shaped 'collapsible'  jigs. He used a thinnish, dense card stiffener of about 0.8mm thickness and emphasised the importance of skiving (or chamfering) the cards along their parallel edges, in order that the visible outer-hinges on the finished bellows (i.e. the top bindings), do not look thick and clumsy. Such would be prone to showing a crease along the apex when the bellows are extended. Those creases would be stress-concentrators and fatigue along them will ultimately lead to cracking, air leaks and failure. Admittedly, this might take a few years to happen!

I believe that 'old school' concertina makers all used thinnish cards: this would in itself reduce the potential difficulty to some degree. Whether they further chamfered the card edges probably depended on the quality and price of the instrument they were making. The supposed differences in construction required (it is asserted by some!) for 'Anglo' and 'English' bellows is probably mythological - - ( English concertinas inherently being more expensive than Anglos, were more likely to have had higher-quality bellows made) .

In looking at some 'vintage' instruments, even after 100 years or more of use, the original bellows of some (notably Wheatstones, (but even quite an ordinary, venerable Lachenal 'English' that my partner plays and has had much usage), may show very little degradation on the apexes of the top-bindings, which still look compact and neat.

Having made a few different sized bellows myself, I can see the attraction to the maker or restorer of using recent, rather ingenious methods of bellows construction that obviate the making of complicated jigs before you even start! One that I'm thinking about in particular uses what seems to be rather thick (well over 1mm) card which is cut-out in part sing a band-saw. This whole bellows-making procedure is described admirably in a video freely available on 'the net'. Whilst celebrating the simplicity and versatility of this invention, one can't help noticing the 'clunky' top bindings that can result. These have maybe a squarish look, a tendency to show a crease when the bellows are extended and perhaps a reluctance to close properly. One wonders how many of these will still be functioning in 100 years' time? Could not one parallel edge of the cards be skived (chamfered) on opposing faces? Surely a simple-enough operation that needn't add significantly to the cost, one might have thought. To be fair, some modern bellows-makers, who don't do this as 'standard', may offer it in a moderately-priced upgrade, but they will need asking!

I'd imagined that this topic would have been well-aired in these forums already. Having trawled through this forum's history, I found a brief discussion on back-page 80 of Oct 2006.

I only felt motivated to raise the subject again, having a few months back asked a restorer to quote for replacement bellows on an old Lachenal 'Anglo' of mine. Having mentioned what seemed to be quite an extravagant price, this restorer then astounded me by his apparent ignorance  -  or dismissiveness?  -  of such refinements

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If anyone has found a UK source of dense 0.8mm card that is stiff enough for bellows and not prone to delaminating I'd like to hear about it. I'm currently using 1mm millboard from Hewit. Vintage bellows that I have dismantled did seem to use a slightly thinner, denser card (possibly laminated from two or more layers of thin card?).

 

I make mine from individual cards and chamfer the top edge of each one using a belt sander (I've tried skiving with a knife in the past but got less consistent results). I no longer assemble them on a collapsible mould because I like to be able to move them as I glue the parts on, to reduce the amount of tension built into the hinges.

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Hi Dave,

I only registered as member a month ago, so I'm as new as you will get!

This is my first reply on Concertina.net!

I use 1mm non-laminated carton for making the bellows.

I'm using, if we can call it the "Bob Tedrow Method", but instead of cutting the carton on a band saw I let it being cut by laser.

I use 3 jigs for the assembly.

After the first gluing of all the strips at the peaks and valleys I fold them and use the first press and let it settle for a few hours.

I then use the revolving jig for all the subsequent gluing of  all the leather and finally I put it in my hexagon press and keep on tightening it for about a day.

The jigs are very crude but it works fine for me. The pictured bellows are one I made about 2 years ago and I use it for my tuning setup.

It has 7 folds and measures 32mm across the first and last fold. (4.6mm per fold)

20190331_095305.jpg

20190331_095444.jpg

20190331_095331.jpg

20190331_101337.jpg

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On 3/24/2019 at 12:10 PM, alex_holden said:

...I make mine from individual cards and chamfer the top edge of each one using a belt sander...

Would it be possible to carry out this operation using one of the cutters used by picture-frame makers

to bevel the inner edges of photograph mounts? Just wondering...

 

 

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2 minutes ago, lachenal74693 said:

Would it be possible to carry out this operation using one of the cutters used by picture-frame makers

to bevel the inner edges of photograph mounts? Just wondering...

 

 

 

When I said skiving with a knife, that's what I meant really. I made two sets of bellows with that method but have given up on it because the carriage with the knife blade in it wobbled about too much, causing an inconsistent edge on the card strip.

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As said previously, I raised this topic afresh only because of the seemingly ignorant and offhand attitude displayed on the subject of chamfered bellows cards by one restorer that I made enquiries to. Its good to see that some people are 'aware' and making sensible responses.

Although its some time since my last concertina construction, for the record, I did have to glue 2 cards together to get the thickness I wanted and I did use a belt-sander to do the chamfering!

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Posted (edited)
On 3/31/2019 at 12:39 PM, alex_holden said:

 

When I said skiving with a knife, that's what I meant really. I made two sets of bellows with that method but have given up on

it because the carriage with the knife blade in it wobbled about too much, causing an inconsistent edge on the card strip.

 

Thanks for that. I have a couple of non-concertina projects in hand which require a lot of cutting of card, and beveled (skived)

edges might be an option for some of the large(and thicker) components (*). I have a cutter which cuts 'square', and had been

wondering about buying something which would allow me to do beveling of thicker card stock - maybe I should reconsider, in

view of your comments.

 

I had tried doing it (beveling) 'by hand', but the risk of getting chopped-off finger-ends mixed up with the card was too much for

my delicate nature!

 

Thanks again.

 

(*) Fortunately, smaller (and thinner) components can be managed with a pair of sharp scissors. I don't imagine that would do

for bellows card...

Edited by lachenal74693

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Alex, to skive the edges of the trapeziums I use my leather skiving machine which has a circular blade and works very well (skive the full length before cutting the trapeziums.

Mike

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1 minute ago, Mike Acott said:

Alex, to skive the edges of the trapeziums I use my leather skiving machine which has a circular blade and works very well (skive the full length before cutting the trapeziums.

Mike

 

Which sort of skiving machine is that Mike? I only have a Scharf-fix.

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Posted (edited)

Alex, My machine is a Chinese copy of a German one made by Fortuna .  Mine was made by Wimsew I cannot locate any more info on the net. Mine came via e bay and I had to  about 16 years ago and still runs very well. The machine was collected from the vendor in Shropshire. The copy is so accurate that parts are compatable with the much more expensive machine.

Mike

Edited by Mike Acott
spelling errors

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4 hours ago, Mike Acott said:

Alex, My machine is a Chinese copy of a German one made by Fortuna .  Mine was made by Wimsew I cannot locate any more info on the net. Mine came via e bay and I had to  about 16 years ago and still runs very well. The machine was collected from the vendor in Shropshire. The copy is so accurate that parts are compatable with the much more expensive machine.

 

That's very interesting, thanks.

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