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Andreas Preuss Super-Light-Violin Project


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Tired after a long working day on the back of the super light violin.

Got the back down to 137g so far with pretty high X mode (which is my main criteria for stiffness) Thickness in the center around 4.5 (I misplaced my thickness gauge and worked only with the punch marker.) and in the lungs between 3.5 and 4.0 leaving enough room for weight reduction from the outside when the fiddle is assembled and playable. Just feeling the stiffness of the plates by twisting it in my hands 30g reduction should be possible to reach my goal of 107g. Just going down 22% of the thickness will bring the result.

 

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8 hours ago, Torbjörn Zethelius said:

 I noticed.  What’s the point? 

It is the point where the straight lines of the arching meet.

Maybe no significance at all. It just landed there and was a bit above the true geometrical center. Right now I don't have a dozen of del Gesus in my shop to verify if this is the explanation for the pin hole above the center.   

:rolleyes:

 

 

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1 hour ago, Torbjörn Zethelius said:

Andreas, did you explain these lines before? What are they? Why are they there?

Sorry, I actually didn't explain them. When I make the arching starting from the inside I use a straight ruler as a guide not to dig too deep. In particular in the areas where I drew the straight lines it is pretty easy to loose control and go deeper than necessary. Those straight lines in the arching give me always the feeling to create something like a lean, athletic arching. Because my violin is not symmetric the straight lines are placed not like a mirror image, so on a (more or less) symmetric violin the straight lines can be used as well to check the symmetry of the arching. 

(Just to be precise: I have drawn the lines up to the drill point but they are actually curved slightly at the end before reaching the hole something like 10mm)

But as I am planning to carve the thickness from the outside on the playable instrument I came up actually with a second idea how to use the point where the straight lines meet(which I drilled through to the outside.) Those lines could be used as a reference to know approximately how much material you take from the outside (without using a magnetic thickness gouge.) which was certainly a concern for violin makers in the 18th century, supposed they worked that way. (no claims that they DID work that way)

If you want to have a more complicated theory about straight lines iin an  arching you can contact your compatriot Robert Zuger.

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Thanks. Do you mean that you use the shadow from the ruler to check the curvature? I do that too, although the lines aren't quite in the same location. A good sequence to work is to go from the deepest point towards the edges. Maybe you do that already. Zuger's straight lines will automatically form in the arch due to its curvature. I don't see it necessary to focus on them IMO. But maybe I misunderstood something?

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3 minutes ago, Torbjörn Zethelius said:

Thanks. Do you mean that you use the shadow from the ruler to check the curvature? I do that too, although the lines aren't quite in the same location. A good sequence to work is to go from the deepest point towards the edges. Maybe you do that already. Zuger's straight lines will automatically form in the arch due to its curvature. I don't see it necessary to focus on them IMO.

I have used all sorts of methods in the past  and switch back and forth depending on my mood and what I want to make. (Ruler shadow method, chain method, circle method etc.)

On my super light violin I was a kind of following my instinct. I placed a hard straight edge on the surface and smoothed out the big bumps (meaning where I thought there is still too much material).  ididn't care too much about smaller bumps. I find the flanks always most tricky to get right and for this I find the straight lines just genial. 

While working I realized that the lines almost meet in one point so I made the last small corrections in one bout to make them meet.

Of course it is almost impossible NOT to  get straight lines but the more you 'bomb' the arching the more the straight lines drift away at their outer ends form the center which gives you an indication as well for that. (how blown up your arching will look like)

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Scroll inspired by the Leduc Del Gesu. The pencil lines show the new type of graft. The pegbox is hollowed to the extreme. Weight is 26g. Compared to a cut off schoenbach scroll 10g less.

The graft will be made from spruce to save weight without sacrifying any stability. in theory the spruce neck should have even more stability than a maple neck. I am concerned only about how it will wear long term. 

So far happy with the progress.

image.jpeg

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3 hours ago, finnfinnviolin said:

Hi Andreas, 

 

whats the idea behind this ‘new’ type of graft? Will the G peg be termed through the spruce neck graft? 

Hi Finnviolins,

Originally I was thinking of using the Knilling planetary pegs, which are glued into the holes. But then I realized that they are circa 10g heavier than boxwood pegs. 

So now I am still using the idea of making a graft with a lighter material and Because the peg box walls are pretty thin from the beginning every peg hole will be reinforced with a spiral bushing.

This will be the only part of the violin where the use of a different material will be visible from the outside. 

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On 3/23/2018 at 7:37 PM, Andreas Preuss said:

This is how I Imagine to minimize the weight. All figures are pessimistic estimates about how much weight can be saved:  ...

     16.Use Knilling Pegs -3g

On 3/23/2018 at 9:40 PM, Don Noon said:

Are Knilling pegs actually lighter?  I haven't used them, but I thought they were similar to PegHeds, which have metal gears and are much heavier than wooden pegs.  The lightest ones I have used were boxwood.

On 3/23/2018 at 9:40 PM, Don Noon said:
17 minutes ago, Andreas Preuss said:

Originally I was thinking of using the Knilling planetary pegs, which are glued into the holes. But then I realized that they are circa 10g heavier than boxwood pegs. . 

Told ya so. :P             Hmmm... can't seem to fix the odd format boxing here.  Oh, well.

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On 5/13/2018 at 11:23 AM, Nick Allen said:

Is the heavy undercut to save weight?

Yes, if you wanna save weight, you gonna do it wherever you can. But actually I have a second though in the back of my head.

If I ever should find out that the head NEEDS weight that the violin functions this will be the ideal spot to hide a small weight and eventually adjust it to what one thinks brings the best result.

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  • 2 weeks later...
35 minutes ago, JacksonMaberry said:

Very cool! That spruce neck is going to look wild. Are you intending to treat the finished neck surface in any way to make it more resistant to wear?

Yes, that's an issue. I was even thinking of a maple veneer but that seems to get too complicated. So for the moment I am thinking to soak it with diluted Amber varnish. This should prevent the worse.

 

 

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