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Julian Cossmann Cooke

Clamping the top to a rib garland with blocks at...

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3 hours ago, Anthony Panke said:

I still ask the question, is one of the surfaces flat?

What would this have to do with tension and the rib structure?

sadly I don’t have any apprentices. I do the outside first, but leave the edges and purfling channel til the body is complete.

i feel (and this is just speculation) that the belly vibrates better without extra tension. Take for example the sound post. If you make it 2mm too high, if it fits in the instrument you will kill the sound, not to mention damage the belly. 

So I make the surface for the back flat, and the whole thing warps after a while. When I plane/sand the belly surface flat, the rib heights are uneven. 

Hi Anthony - not very much actually.

I've heard - ribs parallel, uniform taper from bottom to top, taper from upper c-bouts to top, even asymmerical taper, ratio of upper bout volume to lower bout volume - now a new one emerges taper from the c-bout blocks to top and to bottom - maybe we should make a sanding board. with a spherical surface - but with what radius?

All these theories - all these theories - just so long as it works.

cheers edi

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I suspect that taper doesn't have as much to do with my violins getting better as all the other things that improved as I made more. I still do it, but like DB said I'm feeling confident that the arching and grads are more where the rubber meets the road. 

@Andreas Preuss I don't remember the taper/Baroque fingerboard thickness relationship. Would you please link me the the article where Hargrave discusses that? Thanks!

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5 hours ago, Anthony Panke said:

I still ask the question, is one of the surfaces flat?

If this question is about some 300+ year old instrument, there's no way to know how it started, with all the distortion that happens over that amount of time. And also...

For new building, most methods involve removing the garland from the form, and then gluing it as best as possible to one plate or the other.  If you think about it, this is gluing a noodle to a noodle, so who knows how it will end up.  Then the remaining noodle (plate) is glued to this now semi-rigid garland/plate that you don't know exactly what it is now anyway.  

I'm not worrying about it.  Everything is pretty flexy until both plates are glued onto the garland, so I just want to make sure the overhang keeps about right and not obsess about what's flat or not and what's tweaked a little to glue it down.

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1 hour ago, edi malinaric said:

Hi Anthony - not very much actually.

I've heard - ribs parallel, uniform taper from bottom to top, taper from upper c-bouts to top, even asymmerical taper, ratio of upper bout volume to lower bout volume - now a new one emerges taper from the c-bout blocks to top and to bottom - maybe we should make a sanding board. with a spherical surface - but with what radius?

All these theories - all these theories - just so long as it works.

cheers edi

I like the idea of a spherical surfaced sanding board, edi.  I think we could all agree that it would result in an instrument with a round sound.  :P

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29 minutes ago, Julian Cossmann Cooke said:

I like the idea of a spherical surfaced sanding board, edi.  I think we could all agree that it would result in an instrument with a round sound.  :P

Hi Julian - isn't it called a banjo?

cheers edi

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1 hour ago, edi malinaric said:

Hi Julian - isn't it called a banjo?

cheers edi

Nope... they're round but flat, not spherical.

Maybe this:

2444956_orig.jpg

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2 hours ago, JacksonMaberry said:

I suspect that taper doesn't have as much to do with my violins getting better as all the other things that improved as I made more. I still do it, but like DB said I'm feeling confident that the arching and grads are more where the rubber meets the road. 

@Andreas Preuss I don't remember the taper/Baroque fingerboard thickness relationship. Would you please link me the the article where Hargrave discusses that? Thanks!

I read it in Hargraves 3 article serie 'Tried and tested'. I don't know if he published it on the net.

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10 minutes ago, Andreas Preuss said:

I read it in Hargraves 3 article serie 'Tried and tested'. I don't know if he published it on the net.

Googling "Roger Hargrave Tried and Tested" has not yielded any results, sadly. Do you recall if these were published in the Strad or similar? I shall comb back through his website library and see if I can come up with what you described.

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Here is a rib to back plate taper suggestion  I found for a Del Gesu violin.  The height at the tailpiece block can be 14 1/2 lignes French and the neck block 13 1/2  l. fr.  Scribe about two inches either side of the neck block using the 13 1/2 lignes french.  The back plate is glued to this taper suggestion - no info. about the belly plate and a taper.

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11 hours ago, JacksonMaberry said:

Googling "Roger Hargrave Tried and Tested" has not yielded any results, sadly. Do you recall if these were published in the Strad or similar? I shall comb back through his website library and see if I can come up with what you described.

This was back in the mid 80s. If my failing memory is correct 1986 or so.

As far as I know Roger revised and refined his view on the working methods reason for which he supposedly didn't publish it on his website.

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5 minutes ago, Andreas Preuss said:

This was back in the mid 80s. If my failing memory is correct 1986 or so.

As far as I know Roger revised and refined his view on the working methods reason for which he supposedly didn't publish it on his website.

Ah, that makes sense. Thanks, Andreas.

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16 hours ago, Don Noon said:

If this question is about some 300+ year old instrument, there's no way to know how it started, with all the distortion that happens over that amount of time. And also...

For new building, most methods involve removing the garland from the form, and then gluing it as best as possible to one plate or the other.  If you think about it, this is gluing a noodle to a noodle, so who knows how it will end up.  Then the remaining noodle (plate) is glued to this now semi-rigid garland/plate that you don't know exactly what it is now anyway.  

I'm not worrying about it.  Everything is pretty flexy until both plates are glued onto the garland, so I just want to make sure the overhang keeps about right and not obsess about what's flat or not and what's tweaked a little to glue it down.

Not really. The few untouched samples have apparently the rib taper. 

But at least we can say safely, it doesn't have much to do with the sound.

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14 hours ago, Don Noon said:

Nope... they're round but flat, not spherical.

Maybe this:

2444956_orig.jpg

Aaah Don - just as we were making huge progress in understanding you have to go and reset the clock to zero???

A whole new set of questions...

- are the f-holes based on a Strad model? which decade? is that the optimum positioning? does one carve them square to the surface or radially towards the centreline?

- is there a best time of the year for harvesting the gourd? preferred species? region? seasoning?

- is the arching done from the inside? is there an approved thickness distribution?

- how is the neck attached? by nail, screw, bolt, mortise, dovetail, friction or glue - details - details

- the top - what is best, goat or sheep skin? what ground treatment gives the best projection?

- I see that the maker uses nails to clamp the top to the body - is it also glued? is there a preferred nail pattern or is it regional in nature?

- a laminated bridge! is this an advance over selected maple? maybe marine ply and so immune to moisture changes?

- looks like the maker knew about the importance of the correct after length, the lightness of the tailpiece and was right up there with a wire attachment...

- any idea of the best strings? or the tuning/pitch used

- what new tools - no - let's not even think of going there!

Questions, so many new questions?

cheers edi

 

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18 hours ago, edi malinaric said:

Hi Anthony - not very much actually.

I've heard - ribs parallel, uniform taper from bottom to top, taper from upper c-bouts to top, even asymmerical taper, ratio of upper bout volume to lower bout volume - now a new one emerges taper from the c-bout blocks to top and to bottom - maybe we should make a sanding board. with a spherical surface - but with what radius?

All these theories - all these theories - just so long as it works.

cheers edi

There are many solutions to this 'problem';)

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5 minutes ago, Andreas Preuss said:

Not really. The few untouched samples have apparently the rib taper. 

But at least we can say safely, it doesn't have much to do with the sound.

Hi Andreas - we could say it, but who is going to believe it? :-)

The only alternative to hours of discussing the advantages of tapering the rib is 100x more hours practising at making a better sound - and that's a lonely activity.

cheers edi

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For support the Roger Hardgrave theorie on the Biddulph book about Del Gésù, here is a pic of the Stradivari 1727 "Reynier" with the mark of the taper on the top side. (please don´t publish it on internet without my credit)

I do it myself on the back side, I don´t feel we should do the same than the classical Cremonese makers!

For have recently removed the top on one of my viola after 6 month, I can say the tension of the back on the ribs..... and neck, is still very strong.

001-ConvertImage.jpg

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On ‎6‎/‎8‎/‎2019 at 1:04 AM, Andreas Preuss said:

If Roger Hargraves theory is correct, this was necessary for the neck setting in relation to the fingerboard thickness when doing it baroque style.

I personally think this is the better explanation as opposed to there plantation of building in tension on the top. The latter is in my view only the attempt to make sense of the taper from top corner blocks to top block on old (Italian) instruments without knowing where it came from.

If you want to the same  on a modern instrument, I wouldn't make 2.5 mm difference, 1.0 to 1.5 is enough and can be done by clamping the top down to the ribs. Maybe you have to make a few shavings around this area for a perfect fit.

 

This explanation makes sense to me. Didn't Roger Hargrave also say that the taper was only on the belly side?

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34 minutes ago, christian bayon said:

For support the Roger Hardgrave theorie on the Biddulph book about Del Gésù, here is a pic of the Stradivari 1727 "Reynier" with the mark of the taper on the top side. (please don´t publish it on internet without my credit)

I do it myself on the back side, I don´t feel we should do the same than the classical Cremonese makers!

For have recently removed the top on one of my viola after 6 month, I can say the tension of the back on the ribs..... and neck, is still very strong.

001-ConvertImage.jpg

Christian, thanks for this. I think we discussed it on Facebook a few years ago, briefly. I also taper on the back. 

What has always struck me as off about this line on the Reynier - if the line was intended to guide the tapering of the ribs, why is it still there and visible? Did Omo screw up? 

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It´s , for me, the height at the top block (30mm), running parallel of the back,  but going to far on the ribs, it´s why it´s still visible. After 1725, the instruments are not as well finished than before.

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31 minutes ago, christian bayon said:

It´s , for me, the height at the top block (30mm), running parallel of the back,  but going to far on the ribs, it´s why it´s still visible. After 1725, the instruments are not as well finished than before.

Makes a fair bit of sense to me! Thanks. 

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On 6/9/2019 at 1:27 AM, Andreas Preuss said:

Not really. The few untouched samples have apparently the rib taper.

Yes, they have the rib taper, but I don't think we have any way on knowing today whether this taper was done on the top or the back.

One theory has been that since the neck was nailed to the ribs, there probably couldn't have been perfect alignment between the bottom of the neck heel, and the bottom of the upper  block, so a little would need to be shaved off to get a good joint with the back.

I'm a bit more fond of explanations which have more to do with practical shop working methods, than those which rely on original violin design by Da Vinci, or space aliens.

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One of the advantage to taper the belly side on the upper part is to have a sharper angle of the strings at the bridge (imagine the upper nut 2 mm lower) and to rise the pressure on the bridge. A kind of "renversement avant la lettre"

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38 minutes ago, David Burgess said:

I'm a bit more fond of explanations which have more to do with practical shop working methods, than those which rely on original violin design by Da Vinci, or space aliens.

Good to hear.  You wouldn't shouldn't have a problem with me suggesting to Luis and Christian to adopt the back taper for the Portuguese only method of violin making.  Davide, Manfio, Tango and Michael S. are allowed to tag along, if they choose too.  

Seriously though, I'm going to look into this back tapering in the future.  A just slight taper for the back just may slow down a sagging neck during a lifespan of a violin - I can't seem to make the same determination for a belly plate taper though or yet.     

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