Violin Forum/Message Board

dalpets

I just realized that there appears to be a discrepancy for the full size Strad 4/4 1716 mold ie., between the Strad poster (356mm) & the online violin manual (313mm)??

I have chosen & completed a Stradposter raw mold @ 356mm but need accurate dimensions to cut out all the block positions.

Some help would be appreciated

Thank You

Michael Darnton · Posted: Sun Jan 16, 2022 1:12 pm Post subject:

Since you don't post your precise sources, we can't know if they are measuring the same thing, but 313 mm doesn't sound like anything on a violin and 356 does not sound like any Strad mold dimension--are you referring to the Messiah total back length, not the mold?
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dalpets · Posted: Mon Jan 17, 2022 2:04 am Post subject:

My mold is based on the Strad poster of the full size 4/4 image of the 1716 'Messiah'.
Unfortunately there is no provision here to post an image of that poster and which cannot be otherwise viewed unless purchased.
A one line extact of all the dimensions states;
'the measurements are taken with calipers & are the length taken from the side of button for the back (356mm) & belly (356mm)'

The reference to 315mm is from the online violin manual @
http://www.makingtheviolin.com
The size is based on my calculations of the individual measurements on that image.
I can't really see how a generic reference such as this is of any value to anyone beyond mere generalised theoretics!

What do you say the full length of this 1716 mold should be?

Michael Darnton · Posted: Mon Jan 17, 2022 12:49 pm Post subject:

You are measuring different things, neither of which is the form length. The poster size is the length of the body, which includes ribs and overhang (at each end) beyond the form size. Your "form" size is the distance between the blocks, but the total form length includes the blocks. Ribs and overhang add 7mm to the form size.
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dalpets · Posted: Mon Jan 17, 2022 11:55 pm Post subject:

You are assuming I am reading off the full size pictures on the poster. That is not the case. I am reading off the full size line drawings thereon. Why would they go to the trouble of producing line drawings if they were not useful for producing a form?

I checked my poster & there is indeed the approx differnce you state between the full size picture of the basic violin corpus & the full size line drawings. I have used the latter for the form.

This is a very professionally done large gloss poster not to be sneezed at as an amateur attempt.

See https://www.thestradshop.com/store/thestrad/antonio-stradivari-messiah-violin-1716-poster/

When you get onto ths above address double click on the faintly printed section that includes the line drawing referred to.

Could we now move on to my OP?

Michael Darnton · Posted: Tue Jan 18, 2022 12:19 am Post subject:

The line drawing is of the full outline, not the mold. So take 7 from 356, you should have a mold measurement of 349, including blocks. I can't make anything of the other site. He does not seem to make it possible to get a measurement total nor show where the end of his measuring points are. It just looks like a hot mess to me.
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Michael Darnton · Posted: Tue Jan 18, 2022 12:20 am Post subject:

The line drawing is of the full outline, not the mold. So take 7 from 356, you should have a mold measurement of 349, including blocks. I can't make anything of the other site. He does not seem to make it possible to get a measurement total nor show where the end of his measuring points are. It just looks like a hot mess to me.
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dalpets · Posted: Tue Jan 18, 2022 12:24 am Post subject:

There are two corpus line drawings in the mix of the poster. One has a double lining the other a single lining.You are correct, thanks.

I have used the non-mold version so I need to make a change. A trap for new players!

Does this mean I can reduce my existing mold all round by 7mm or wouldn't that be kosher? Or do I need to start afresh?

Do you have anything for me on the OP re block geometry, ie., if any such thing exists in practice?

Michael Darnton · Posted: Tue Jan 18, 2022 10:42 am Post subject:

I would take off another mm or so, because things have a tendency to grow! Marking lines are always outside the template, never exactly corresponding to the template.

It would be better to start over. If you move inward from what you have now, you will end up with cumulative errors. Every generation removed from the original gets worse, more inaccurate.

The only problem area will be corners. The plates do not exactly follow the mold and there are other issues as well. One is that the corners will come out longer than you think. Check out my book page http://violinmag.com . There is an article about original Strad corner block shapes. You may also find this library interesting: http://www.thestradsound.com/maestronet/stradivari-forma-by-addie
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dalpets · Posted: Wed Jan 19, 2022 1:01 am Post subject:

As far as molds are concerned all I can see in the wild are CNC knockoffs & we all know that the manufacture of knockoffs spreads like viruses with potential for varying degees of error.

Interestingly, none of these knockoffs currently provide details of dimensions. So the Strad 1716 knockoff mold may have many iterational errors in the wild, producing very ordinary results.

So where & what were the resources available to the luthier/violin maker to make an accurate mold from scratch before the arrival of CNC?

Where are those resources today?

Michael Darnton · Posted: Wed Jan 19, 2022 2:04 am Post subject:

The modern mass produced molds I have seen have been ridiculously bad and a waste of money. The recent "old" way was to find a violin you liked and take a tracing from it. To draft one from scratch we'd have to know how They did it, and we don't. There are life size photos of Strad's molds and so we can copy those. I have done both--copy molds and copy tracings.
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dalpets · Posted: Wed Jan 19, 2022 10:51 pm Post subject:

Michael Darnton · Posted: Wed Jan 19, 2022 11:47 pm Post subject:

No, not exactly. If your snit were justified I wouldn't even be talking with you, but I am. My warning was directly at the bad molds you can waste a lot of money on.

I have worked from STRAD posters, too. But not from their tracings. Once you have the measurements you can have a Xerox copy of the poster made to the exact size, glue it on a sheet of 1/2 inch plywood and hack out a form directly. Thats a pretty good way to get a good form. If you cut to the outside of the purfling you will get a good shape and size (a hair small, but as I said, they grow), assuming that the picture is undistorted. If you have Photoshop skills and a large printer you can get something even better.

If you want good Stradivari mold pics ready to work from, they're on the web somewhere, too--all of the existing ones. I believe they are buried somewhere here, last time I looked: https://traitedelutherie.com/
OK, nope, he took them down...
Well, drawings abstracted from the same forms are here: http://www.thestradsound.com/maestronet/stradivari-forma-by-addie
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dalpets · Posted: Thu Jan 20, 2022 1:52 am Post subject:

Buried is the operative word!
The Addie database seem to do the trick for correct dimensions.
Pity we could not have gone there from the get go.
If any other potential questions I might have are as circumventively answered I will have a posthumous or unfinished violin.

You say you have used a poster (Strad 1715 'Messiah' ?) Did you use it for mold production? What was your view of its worthiness in respect to accuracy?

Michael Darnton · Posted: Thu Jan 20, 2022 9:40 am Post subject:

I did not use the Messiah poster. It's probably fine. After the mold pictures became available I have worked from those when I can. I'm sure something derived from the poster if you pay attention to the measurements. The biggest danger in this is that Cremonese instruments are usually a bit lopsided and photos which aren't shot straight on can be lopsided in other ways, so you can never be sure if the source of distortion is original or photo. I often will pick the more attractive side (left or right) and flip it to make the other half of the full outline. But that's not strictly correct, either.

I'd warn you now to not be too casual about all of this. Someone who knows violins will spot problems long before you will with your inexperienced eyes, so you would do well, if you are serious, to learn to know what you are looking at. That's hard at the start. Care in making templates is a start--even if you don't see the underlying structure a carefully made and followed template can unintentionally replicate it.

Remember, I can only answer questions that you ask--I can't predict what you will want to know at any given moment.
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