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fiddleharry

Top/bottom plate thickness mesaurement

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Is there a way to measure the violin Top/bottom plate thickness without taking the violin apart? What tool do I need for such type of measurements?  I am particularly interested in the center region of the bottom plate. Thank you.

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Hacklinger gauge, reasonably accurate,  reasonably expensive but worth it over work career. But nothing more fun than removing a top carefully welded on.

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If I recall, recently someone posted a new gauge on MN, too.  I'm happy enough with the Hacklinger, which probably can still be bought at Core, IV, or Shar.  Used to be about $365.

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Hacklinger every time. He made one especially for me to do the Strad posters. Without him many would not have been possible. I have tested mine (I have two) many times and they are accurate to one tenth of a millimetre. More than enough for most violin makers.

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Hacklinger gauge, reasonably accurate,  reasonably expensive but worth it over work career. But nothing more fun than removing a top carefully welded on.

Thank you for the info. ~$400 is not cheap and is about another fix upper violin off the internet, But this tool should tell me which ones deserves the open belly surgery :)

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Just as mean averages are not accurate measurements, accurate measurements are not mean averages. Although Hacklinger measurements are accurate when taken from specific points, the points themselves are subjective. Even the slightest departure from such a point will resulted in a different reading. This is the case with every method of measuring. The question is, how accurate do we need to be.

If we measure an accurately machined piece of metal plate, its thickness will also vary if the above criteria is applied. However, in this case we may be talking about thousands of a millimetre. Do we really need to worry about one tenth of a millimetre here or there on a piece of wood? If so we are working with the wrong materials and wrong tools.

Are we expected to believe that such masters as Strad and Amati worked to such tolerances? I think not. As for Del Gesu, no-one could accuse him of such naval gazing.

I just missed Linkman's colourful contribution. I have tried this method and it works well enough. However, the same applies to this piece of equipment as it does to the Hacklinger. The problem for anyone who is into navel gazing, is that in spite of the magnet, the ball tends to find the deepest (thinnest point). Ooooooowah!

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What is the max thickness that these two tools can measure? I am thinking at the center of the bass bar + the top plate, the total thickness could be up to 40mm. If these two devices can handle the ~40mm thickness, it's also a good way to assess the location of the bass bar and see if it's properly oriented.

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None of the magnetic gages will work to measure a bass bar height, which should be more like 15mm, not 40mm.

Even if it can handle those dimensions, the shape of the bass bar would prevent getting the inside ball into a stable position on top of the bar.

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As long as you use these gauges carefully, there should be no serious differences between the measurements taken by two different people. But quite honestly these measurements are only a guide to the overall thickness of violin plates. In case anyone missed it. As I said in post #11, unless you are being particularly anal, it does not matter a hoot if your measurements are out by one, or dare I say, even two tenths of a millimetre, natural blemishes in the wood will see to that. The question is; will two tenths of a millimetre on one or two measurements tell you what the maker was trying to achieve? And will you really be working to such accuracies on your copy, while ignoring the properties of the wood with which you are working? If that is the case purchase a laser copier and the job will be perfect. It will cost a sight more than a Hacklinger, but at least you will sleep well at night.

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Looks more like a colonoscopy tool retrofitted for violin making...

Careful, Julian. I recently got reamed here for using the word "stiffy". :D

 

Some people have such filthy minds, that they are obsessive about interpreting everything in the dirtiest way possible, :o despite other options.

 

1419613.jpg

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If you look at Strad's thickness gauge shown in Hill's book on Strad  I don't think a tenth more here or one less there concerned him.  fred

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As long as you use these gauges carefully, there should be no serious differences between the measurements taken by two different people. But quite honestly these measurements are only a guide to the overall thickness of violin plates. In case anyone missed it. As I said in post #11, unless you are being particularly anal, it does not matter a hoot if your measurements are out by one, or dare I say, even two tenths of a millimetre, natural blemishes in the wood will see to that. The question is; will two tenths of a millimetre on one or two measurements tell you what the maker was trying to achieve? And will you really be working to such accuracies on your copy, while ignoring the properties of the wood with which you are working? If that is the case purchase a laser copier and the job will be perfect. It will cost a sight more than a Hacklinger, but at least you will sleep well at night.

 

Hi Roger,

I mainly agree with what you say there. But I still maintain that two luthiers with different questions/ prejudices measuring the same instrument with the same gauge can come up with a significantly different overall result.

 

Please allow me to tell a story against myself to illustrate the point

 

I  have gone back to re measure instruments and come back with different results. In the first instance many years ago I measured a Cremonese cello thinking that a 20 or so basic measurements were all I'd need and naively presuming that the gradations must be smooth and gradual. A few years later I was very lucky to get a CT scan of the instrument....It made a mockery of my understanding of the gradations. Yes all my original  Hacklinger measurements were correct but there were not enough of them to show that the back of this cello had a very pronounced narrow thick spine in the upper and lower bouts for instance. Had I been measuring in a different way with a different attitude.. I might have come closer to what the CT scan revealed.

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Hi Roger,

I mainly agree with what you say there. But I still maintain that two luthiers with different questions/ prejudices measuring the same instrument with the same gauge can come up with a significantly different overall result.

 

Please allow me to tell a story against myself to illustrate the point

 

I  have gone back to re measure instruments and come back with different results. In the first instance many years ago I measured a Cremonese cello thinking that a 20 or so basic measurements were all I'd need and naively presuming that the gradations must be smooth and gradual. A few years later I was very lucky to get a CT scan of the instrument....It made a mockery of my understanding of the gradations. Yes all my original  Hacklinger measurements were correct but there were not enough of them to show that the back of this cello had a very pronounced narrow thick spine in the upper and lower bouts for instance. Had I been measuring in a different way with a different attitude.. I might have come closer to what the CT scan revealed.

Of course CT scans give us a far more accurate picture and above all they provide us with complete rather than partial images. They are also truly beautiful. Times have certainly moved on, but for average Joe's like me, the Hacklinger is probably the best alternative to buying a CT scanner.

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