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PostPosted: Sun Sep 03, 2017 3:27 pm 
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Cocobolo
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Hi,

I've been given some very old gabon ebony, since it's often difficult to see the grain orientation on ebony, my question is: in general is it really important for an ebony fingerboard to be perfectly quartersawn?

Image

Image

Thank you

Q.


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PostPosted: Sun Sep 03, 2017 4:11 pm 
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Brazilian Rosewood
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In general, yes. Flatsawn Ebony can have a nasty tendency to cup, and at 1/4 thick has quite a bit of power behind it, so it can cause problems.

The good news is, with the log half in your picture, you should be able to easily identify the grain orientation and cut accordingly. Hope it's nice on the inside!


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PostPosted: Sun Sep 03, 2017 6:28 pm 
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Cocobolo
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Wow! You're lucky to have that billet. Many years ago I bought two logs from Gilmer Hardwoods in Portland, Oregon of Madagascar Ebony and sawed them myself. The dust turned the whole shop black even though I had dust collection on the resaw. It's the best ebony I've ever used and I still have several fingerboards of that lovely stuff that I've hoarded for special builds. Why are you worried about "flat sawn" just be careful setting up your bandsaw and if necessary saw in radial passes. You'll end up with beautiful quartered fingerboards. What a find! That stuff is like gold.


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PostPosted: Mon Sep 11, 2017 8:51 pm 
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Walnut
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I too have wondered about this.I see more and more flat sawn gabon boards from the smaller factory brands as time goes by.

I thought that movement in gabon would be minor because of the density of the wood itself,as long as it's well dried.


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PostPosted: Tue Sep 12, 2017 1:39 am 
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Gabon Ebony Shrinkage - Radial: 8.3%, Tangential: 11.2%, Volumetric: 19.6%, T/R Ratio: 1.3
For comparison, the neck wood perhaps is Hog - Radial: 2.9%, Tangential: 4.3%, Volumetric: 7.5%,
EIR - Radial: 2.7%, Tangential: 5.9%, Volumetric: 8.5%
African Black Wood - Radial: 2.9%, Tangential: 4.8%, Volumetric: 7.7%.

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These users thanked the author Colin North for the post: dpetrzelka (Tue Sep 12, 2017 9:16 am)
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PostPosted: Tue Sep 12, 2017 5:02 am 
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Looks like ABW is a near perfect match for mahogany, at least on paper, Colin.

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PostPosted: Tue Sep 12, 2017 11:50 am 
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African Blackwood is imo the perfect fingerboard wood. Except that it's expensive and hard on tool edges.

I guess most ebony blanks that end up as fingerboard are far from quartered and folks use it all the same. In my last guitar I had a better quartered piece of ebony (easier to see because it was not jet black, more of a grey black) and the pores were larger than usual. I wonder if QSawn ebony shows the pores more effectively?

Great find!

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PostPosted: Tue Sep 12, 2017 12:19 pm 
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I'm uncertain of the meaning of shrinkage data. As I understand it, it is done by measuring a block of green wood, then drying it and re-measuring.

What I don't know is are the stated shrinkage values indicative to what happens when a dry piece of wood is moved from a 40% RH to say, a 60% RH?

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PostPosted: Tue Sep 12, 2017 12:28 pm 
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Brazilian Rosewood
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I've never liked ABW for fingerboards as it is terribly stringy when routing for inlays, but loved using it for bridges. Rings like a bell when dropped on a saw table. Ebony goes "thud".

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PostPosted: Tue Sep 12, 2017 1:24 pm 
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Joe Beaver wrote:
I'm uncertain of the meaning of shrinkage data. As I understand it, it is done by measuring a block of green wood, then drying it and re-measuring.

What I don't know is are the stated shrinkage values indicative to what happens when a dry piece of wood is moved from a 40% RH to say, a 60% RH?

IME, the expansion rates do remain similar after drying. Ebony will always move much more than mahogany when the humidity changes. That's why fret ends poking out and cracks along the edges of the fingerboard extension are common with ebony... and why the popsicle brace was invented, to try and stop them.

But since African ebony's quartersawn rate is so high already, and flatsawn isn't that much worse, it's probably ok to use it flatsawn. You're going to have to put up with the problems it causes either way.

Some builders glue the fingerboard with epoxy rather than typical water-based glue. On a large area joint like that, the wood will absorb water from the glue and swell up, then stick in place, and then shrink after the glue dries. And since the ebony swells and shrinks more than the stuff it's being glued to, you get built-in stress. Cupping is also a problem with water-based glues, unless you spread water on the outer face to counteract it. But then you get even more expansion, and more built-in stress.


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PostPosted: Tue Sep 12, 2017 4:07 pm 
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What they said...
And I like it for FB's and bridges, can't afford B & S!

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PostPosted: Tue Sep 12, 2017 5:36 pm 
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Turning squares can be a cheaper source for ABW bridges. I bought three at 1 1/2" square by 9" long that were 2nds for 50 cents/inch. Only one had a crack in one end, so 9 FB's for $13.50. I'll be getting more on Saturday.

Alex

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PostPosted: Wed Sep 13, 2017 3:05 pm 
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Walnut
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Colin North wrote:
What they said...
And I like it for FB's and bridges, can't afford B & S!


I can't afford back and sides either Colin lol

But I do love the smell of it when I worked a few bridges in the past


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PostPosted: Thu Sep 14, 2017 10:53 am 
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the shrinkage percents may be very similar between mahogany and ABW but I would expect ABW to gain and lose mosisture much, much more slowly than hog. I wouldn't count on them moving "together."

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