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Low back arch and higher top arch.


Nick Allen
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Well, I wouldn't make the front flatter than the already quite flat back. 
A flattish back like that might give quite a punchy sound, so figure that in. 
Think about thickness for the back too, what sort of plate do you want to make.
I'd make a front that won't be too punchy, ie not too flat thick and stiff. 
Have a look at well known top fiddles with flattish backs, for guidance. 

Cheers. 


 

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So I am arching my first fiddle, and I've realized that my back arch might end up at about 12.5mm. This is a prediction. So if this is the case, can I compensate for this by making the top arch a little more substantial? Has anyone done this?

I would have thought that 12,5 mm is not much of an arching. The old master instruments that I have personally measured, with my own ruler/calliper etc. over the last decades, are more +/- 18mm., to the point where I wonder what Saconni was measuring.

Viewed entirely unromantically, a violin is a wooden box under string tension. Since the belly gets clinched together, and the back gets stretched, the impression gets created, that old violins, in the meantime have higher belly’s than backs. I think it safe to presume that they started life about the same height though.

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Oi!

 

So I am arching my first fiddle, and I've realized that my back arch might end up at about 12.5mm. This is a prediction. So if this is the case, can I compensate for this by making the top arch a little more substantial? Has anyone done this?

 

Any help would be appreciated.

 

 

Maybe you could try raise the back arch by damping the plate with hot water (but leave dry the center line), then put a 15 mm thick curved  thing underneath, and clamp the back gradually to a flat surface. (I am a beginner and I never tried that)

 

What pold suggests here is possible but not recommended for your first fiddle. Water and maple is destructive if you do not know what you are doing. The likely scenario is that you will end up with an even flatter arch. It takes at least two weeks to do this and the plate must reach EMC.

 

post-37356-0-50128300-1454931660_thumb.jpgpost-37356-0-10884300-1454931669_thumb.jpg

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Nick,

 

The important number here is that this is your 1st violin.

 

Congratulations! This is one mistake you won't have to make again. :o

 

Your choices are to start a new back or to finish this violin with a more normal 15 mm top and learn from this mistake as you will learn from the others you will make on this 1st instrument.

 

On your next one you will remember that the plate can only be as high as the thickness of your rough wood measured about 1/3 of the way from the center line to the edge. :mellow: 

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Nick,

 

The important number here is that this is your 1st violin.

 

Congratulations! This is one mistake you won't have to make again. :o

 

Your choices are to start a new back or to finish this violin with a more normal 15 mm top and learn from this mistake as you will learn from the others you will make on this 1st instrument.

 

On your next one you will remember that the plate can only be as high as the thickness of your rough wood measured about 1/3 of the way from the center line to the edge. :mellow:

Superb advice.

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Personally, I'd just make the back graduations a bit thicker than normal, and then make the top whatever I would have made it in the first place... and press on.  As Nathan says, this is just a first fiddle... and who knows, perhaps the combination might work out just fine.  I don't see anyone jumping in here with evidence that it can't work.  

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Nathan gave some good advice. Some of the best advice that I've gotten is 'great them like etudes'. You'll never make a perfect violin, and it's often more productive to correct the error on the next one, but don't waste a lot of time dwelling on the flaws of previous instruments. Also good for your piece of mind.

My teacher taught me to base the arching height on the density of the wood. Higher density wood needs a lower arching to reduce weight and doesn't need the strength of a high arch. In contrast, lighter wood needs the strength of the higher arch and the weight added by the higher arch isn't an issue with lower density wood. You'll also compensate with graduations, so there are multiple ways to get a good result. You may want a lighter top if you want a higher arch, but don't go crazy with the top arch height.

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Oi!

 

So I am arching my first fiddle, and I've realized that my back arch might end up at about 12.5mm. This is a prediction. So if this is the case, can I compensate for this by making the top arch a little more substantial? Has anyone done this?

 

Any help would be appreciated.

Just stay with the plan.  Use a correct belly height so that you won't have to use a different neck angle, thinner fingerboard, of higher bridge.  Little mistakes are harmless at first but during a build several little ones can start adding up.  The more you get right now the less you'll have to get right later.

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Yeah, you guys are right. The billet was only like 15mm to start with. I got it for like ten bucks is why. So if the tone will likely end up punchy with the flatter back, mellow it out with a slightly thicker graduation seems to be the best course of action here.

 

 Low arch, thicker graduation is a must.....

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Oi!

 

So I am arching my first fiddle, and I've realized that my back arch might end up at about 12.5mm. This is a prediction. So if this is the case, can I compensate for this by making the top arch a little more substantial? Has anyone done this?

 

Any help would be appreciated.

 

I would not hesitate to press forward. You will have enough to worry about besides finished arch height. Compensate by maybe 0.2-0.3 mm more in thickness and move on.

 

The lowest back arch I ever used was 11.4mm for the same reason as you— It was a undersized billet of nice wood I was determined to make work on a Guarneri model. I did the opposite, I complimented the low back arch with a low top arch of 12.55mm

 

post-38245-0-15984200-1458968300_thumb.jpg

 

At an instrument show including world-class makers, I was told by more than one player it was the best sounding instrument in the room. It was the only violin that sold at the show that year.

 

For every rule in violin making there is an exception.

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Oi!

 

So I am arching my first fiddle, and I've realized that my back arch might end up at about 12.5mm. This is a prediction. So if this is the case, can I compensate for this by making the top arch a little more substantial? Has anyone done this?

 

Any help would be appreciated.

Generally top arches are higher than back arches.  So, in short, yes you can make your top higher.  In fact, you SHOULD make your top a little higher.

 

12.5 mm for a back is pretty low.  It is also very low for a top arch.  But there is at least one great violin with a top arch of 12.5mm and that is the "Soil" Stradivari.

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You could use maple and double the edge, like you would on an old top or back that had been planed down over the years. It's not that difficult a repair when you don't have to worry about preserving the original outline or arching. You can easily add 2 mm took your arch this way. I did this for a particularly nice top I didn't want to throw away because it was too short for a proper arch.

M

Ps. This goes along with the long standing tradition of button grafts and ebony crowns when the maple is just barely not long enough.:)

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