Violin Forum/Message Board

[Chris Knowlton]

I am a first-time builder working from the Stradivarius Milanollo poster

I recently took my plates to a professional leuthier to get some direction on my arching. He and his assistants examined the plates and made a number of very useful suggestions. I was shown a number of plastic pattern examples of plates by various makers including a Stradivarius model. My exposure to violins is very limited so this for me was an eye opening event.

One assistant, who is schooled in the art, felt my back plate arching was “very close” but after some discussion and comparisons It was clear that my front plate was too “full” almost as if someone had pumped it full of air (my words), especially in the upper and lower bouts.

In an effort to describe my dilemma, here is a little background:

1. I made my cross arch templates from the Milanollo poster by averaging the right and left horizontal arches. That is, I traced one side, laid it over the other side, and drew a curve equal distance between the two. The arching in the upper and lower bouts did not require much “adjusting”.

2. I used the long arch just as it was shown on the poster (this may have been a mistake but it shouldn’t have caused the plate to be higher or to look too full).

3. My plates did not yet have the fluting cut so the arching as a whole was still about 1mm high.

4. Except for the lack of fluting the arching matches the templates very well.

5. I used contour lines when I refined the arching so I feel that the areas between the templates are at least even and consistent.

6. The plastic Stradivari pattern was radically different (flatter) than mine and it is my understanding that Stradivari’s arching did not vary that much (At least not as much as the difference between my plate and the plastic Stradivari example) perhaps I am wrong.

7. If I lower (flatten) the arching as was recommended, it will no longer match the templates, not even close.


I believe that this person knows what they are talking about, and I agree that my plate looked full by comparison, but the poster templates must be right, or close to it.

Can anyone help me resolve these two conflicting issues?
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[MANFIO]

Hi!

Strads archings are not allways the same and some plates are more distorted than others.

Archings drawings must be "interpreted" since they have been subjected to distortion. The soundpost in general will pull the top up, so that a top that had started 14 mm high 300 years ago may be 15 or 16 mms high now, Sam Zygmuntowicz talks about that in the minutes of the 1995 Dartington Conference.

In general the long arching template is not used, just the transversal archings are using in shaping the archings.

If good, seasoned makers gave you some advices I would follow them, just my two cents. How high is your the arching on your top now?
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http://www.flickr.com/photos/7875988@N02/with/464604020/

[Chris Knowlton]

Hello Manfio, Thank you for your input. The poster shows approximately 17.2 at the highest point. My plate measures 18.5 at the same location but as I mentioned I have not cut the fluting so the arching is still about 1mm too high.

I have the highest regard for you professionals, and I would prefer to go with their/your advice, but being new I don't feel I have the experience to attempt to complete the arching without using a long arch template.

I will post some pictures later.
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[Chris Knowlton]

Well I won't be posting pictures yet as I do not have access to an online storage location.
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[MANFIO]

Ok.... 18.5 on the top seems a bit too high to me... I would reshape it to "safe" 15 mm...

I imagine this Strad was born with a 15 mm high top and, eventually, after centuries of tension and deformation it's 2.2 mm higher now... I guess that this same top got narrowner than the back on the C bouts due to deformation too.
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[Andres Sender]

Chris' goal is the 17.2 shown on the poster.

Manfio kindly quoted the Dartington comments over at M-net and apparently Sam Zygmuntowicz found his top arches rising anywhere from .5 to 1.5 mm.

So that would mean you'd have to decide whether the Milanollo arch is a far-riser or a shallow-riser (and actually that will depend a lot on the final long arch shape, won't it?) So maybe Chris has the option of doing anything from 15.7 to 16.7.

[mikemolnar]

I got a good set of templates from the Milanollo poster only after I decided that there was something wrong with the long belly arch.

I used only the transverse arches and came up with a 16 mm arch which is still pretty high.



Mike

[Andres Sender]

Ah yeah 17.2 must be the long arch figure.

It would be interesting to know whether Sam Z. was measuring changes on the long arch or the cross arches.

[Chris Knowlton]

What about the back plate arching? My back plate, taken from the poster arching, doesn't look bad. Is it typical that the back, being maple and loaded differently, didn't change much, or as much?
The poster measures just over 15mm
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[Michael Darnton]

Something which hasn't been specifically mentioned is that most old violins are warped, lengthwise--slouching, with sunken c-bouts in front, and raised c-bouts on the back--because of hundreds of years of string tension.

Because the long arch is taken with the upper to lower block as a baseline, the other arches, which don't use that baseline (they use the edges at their position) will only fit the long arch if your violin form/ribs are warped identically to the original.

If you're working from a poster it's probably better (necessary, even) to believe the cross arches, build a new long arch based on them, then clean up that long arch, removing obvious lumps, and remake the cross arches as necessary, so that everything fits together on an unwarped rib plane

[Chris Knowlton]

That was it! I transfered the center height of each cross arch to the layout of the long arch and it lowered it from 17.2mm to 15.6mm.
All of the points along the long arch came down except for the lower bout point which went up about a half a millimeter!?

In addition to being too high, my current front plate (still at the 17.2mm height) is very bulky (puffy) in the upper and lower bouts, in the areas that are typically flatter or even concave. The templates in these areas have very short concave lengths. Would this be due to distortion too or is it just the Milanollo design?
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[mikemolnar]

[Chris Knowlton]

Thank you Mike, Andres, Manfio, and Michael.
You guys knew the answer, I just had to hear it 10 times before it sunk in.

I made a new long arch template (I know, but I need it) and after settting it on my over-high plate, it looks like it will take care of a lot of the bloated areas in the upper and lower bouts.

Now I can get back to it, thanks again.

Chris
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[Janito]

A question:

Before reading the advice on the long arch, did the plate arching look right to you?

If not, why did you not believe what your eyes were telling you?

ps - I realise you were working from photos and templates

[Chris Knowlton]

Hi Janito,

The arching looked O.K. to me because I have no prior experience. I have only seen a limited number of violins so as far as I knew, the Milanollo arching was supposed to look that high and full. Everything I did was based on the long arch. As far as pictures are concerned, based on everything I've read, I figured the perspective distorted the look of the arching.

Last week a professional leuthier looked over my plates and showed me many new and old violins and a number of impressions of well known violins including a Strad model. It was immediately apparent that my arching was off, by a lot.

I won't make that mistake again, only the ones that I haven't made yet
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