choice of wood for harmonic bars on tops

Construction and repair of Classical Guitar and related instruments
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geoff-bristol
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choice of wood for harmonic bars on tops

Post by geoff-bristol » Thu Aug 10, 2017 2:05 am

As said - any preferences for wood type on the top harmonic bars ?
On all the 5 tops I have done the fans have been the same spruce - and the bars have been spruce, mostly old bass bar stock I have put aside. But is this ideal ? Any other woods used for these ?

I think the torres bars were often cut at at an angle to the quarter ( ? ) to my mind that suggests use whats to hand - not - Oh I think this needs the grain at an angle ! Any preferences there ?

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Steve Toscano
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Re: choice of wood for harmonic bars on tops

Post by Steve Toscano » Thu Aug 10, 2017 10:35 am

Personally i use either euro spruce (italian or german), engelmann spruce or a local timber to me called King Billy pine.
I believe cedar and mahogany is also common.
All my braces inc harmonic bars are always on the quarter. This isnt so important if useing spruce as it is generally just as stiff flatsawn as quartered.

In a fan braced top im a strong believer in keeping the whole soundboard as light as possible, this reflects my choices of wood for harmonic bars.

Yanguang Chen
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Re: choice of wood for harmonic bars on tops

Post by Yanguang Chen » Thu Aug 10, 2017 11:57 am

I know spruce, cedar, mahagoni, cypress, maple, rosewood or modern material carbon, many material, important factor are suitable density with suitable weight and stiffness of material.
Dipl. -Ing. Yanguang Chen

vesa
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Re: choice of wood for harmonic bars on tops

Post by vesa » Thu Aug 10, 2017 12:56 pm

Bouchet used quatersawn spruce.
His drawings in Cahier d'atelier show very straight grain.
His upper harmonic has vertical grain direction and lower horizontal grain direction.


I use quatersawn sitka. As straight grain as possible, vertical grain direction.
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Antonio Marin nr. 813 1995 (Bouchet)
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simonm
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Re: choice of wood for harmonic bars on tops

Post by simonm » Thu Aug 10, 2017 1:13 pm

Spruce. So far as possible I use offcuts from tops. Otherwise from chunks of spruce bought for the purpose.

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geoff-bristol
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Re: choice of wood for harmonic bars on tops

Post by geoff-bristol » Thu Aug 10, 2017 11:53 pm

vesa wrote:
Thu Aug 10, 2017 12:56 pm
Bouchet used quatersawn spruce.
His drawings in Cahier d'atelier show very straight grain.
His upper harmonic has vertical grain direction and lower horizontal grain direction.


I use quatersawn sitka. As straight grain as possible, vertical grain direction.
Thats interesting ( upper/lower ) I see the logic there - sort of !

Fans I try to get out of the top material - or quartered spruce as close as possible.
I usually use spruce for the bars as I have a great stash of old spruce bits. Less so other light woods.

They are also bars that show in the finished instrument - which maybe is an issue ?

vesa
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Re: choice of wood for harmonic bars on tops

Post by vesa » Fri Aug 11, 2017 5:52 am

geoff-bristol wrote:
Thats interesting ( upper/lower ) I see the logic there - sort of !
Horizontal grain direction makes the LHB to work a bit like a suspension in a car (feathers).
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Antonio Marin nr. 813 1995 (Bouchet)
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Chris Sobel
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Re: choice of wood for harmonic bars on tops

Post by Chris Sobel » Fri Aug 11, 2017 8:27 am

I always use spruce of some sort for the harmonic bars... I've found both sitka and Englemann with awesome strength to weight ratio that I use regularly. I lean towards sitka on my steel string models and Englemann on my classicals. The euro I have is not quite as high s/w but I think that's probably just a source issue--lots of very strong euro out there.

Any wood could work provided it has a high s/w ratio, is stable in service, readily available, and is well cut to minimize runout. I don't think quartered or dead flat would matter all that much as far as stifness... the tests I've seen put them about equal for spruce in brace form. One of the Friederichs I've examined had flat sawn harmonic bars, although this cut is probably in the minority as far as historical use. Flat sawn does seem to bend differently (not weaker, just a different feel) if you sped some time flexing equivalent spruce braces but my knowledge stops there as to whether it's significant or not.
CE Sobel Guitars

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