Suitability of curved grain spruce for top

[TerryOnStrings]

Hi all.

I am a long-time woodworker and amateur-musician working on building my first violin. I've obtained some spruce for the top but unfortunately, the blank was apparently cut near a branch because the grain curves out and back in along the length, not unlike a violin bow. So it is impossible to get a straight-grained joint. This is my first build and I expect it to be a learning experience (mistakes included), so while I'm disappointed in the quality of the wood, I'm prepared to move forward for the experience.  See the attached images (note this is in early stages of planing).

My questions are:
1) Would any professional luthier ever use wood with diverging grain like this? I've personally never seen an such an instrument.

2) Other than aesthetics, would this wood present any structural or sound quality issues?

3) The change of grain occurs near the end of the board so that it would impact about 70mm of the top. Would there be a preference in having this divergence of grain at the upper or lower bout?

Thanks for your thoughts and comments,

Terry

Edited February 19, 2022 by TerryOnStrings
Added additional image

[Andreas Preuss]

As a violin maker I don’t see a problem, if it is good material in relative weight and stiffness. 
 

But sometimes customers think different.

[Don Noon]

For a professional who charges big $$ to sell to someone else, they would most likely not use wood like that, as spruce is cheap in relation to the final price they charge, and their instruments need to look as good as possible.

For someone building a first violin for themselves, this wood is fine.  The grain splay I doubt would be a biggie for tone.  I would put the splay at the lower bout.

[Marty Kasprzyk]

Put the worst curved part under the fingerboard so it isn't as apparent.

The glued plates with the grain at an angle rather than parallel increases the cross grain stiffness of the assembled plate.  This is a similar effect as the bass bar at an angle across the grain of a normal plate.  So I suggest using a shallower bass bar angle than usual.

The likelihood of a bass bar crack would be less with curved grain lines so your wood might be superior acoustically and structurally to the usual straight grained wood.   DG might have liked it because is less expensive and worked better.

Another advantage of using curved grain wood is that it is good for starting arguments on MN.

[nathan slobodkin]

Probably not a big deal tonally and lots of good instruments with weird wood. How ever jointing this piece would mean you were planing up hill some where along the joint which is a real pain. As a beginner give yourself a break and get some nice straight grained spruce with the year rings perpendicular to the inside surface of the plate.

[TerryOnStrings]

Thanks for the replies. Glad that everyone agrees this wood will be fine for a first instrument. Now I just need to decide at which end to place the angled grain.

I can see an argument for both. I agree putting it under the fingerboard will hide the converging grain at the center-line. But it also seems that with the fingerboard tapering in toward the scroll and the grain flaring out on either side, it might actually accentuate the splay. But maybe that's not necessarily a bad thing?

Not sure if that is clear so here's some ASCII art showing the proposed grain-fingerboard-grain at the upper bout:
(\\\\\ /    \ ////)

As far as the planing challenge Nathan mentioned, he is right, but I've already tackled that problem. After experiencing tear-out from either direction I switched to a high-angle frog (55 degrees) and was able to get a good clean, tight-fitting joint.

[Marty Kasprzyk]

3 hours ago, TerryOnStrings said:

Thanks for the replies. Glad that everyone agrees this wood will be fine for a first instrument. Now I just need to decide at which end to place the angled grain.

I can see an argument for both. I agree putting it under the fingerboard will hide the converging grain at the center-line. But it also seems that with the fingerboard tapering in toward the scroll and the grain flaring out on either side, it might actually accentuate the splay. But maybe that's not necessarily a bad thing?

Not sure if that is clear so here's some ASCII art showing the proposed grain-fingerboard-grain at the upper bout:
(\\\\\ /    \ ////)

As far as the planing challenge Nathan mentioned, he is right, but I've already tackled that problem. After experiencing tear-out from either direction I switched to a high-angle frog (55 degrees) and was able to get a good clean, tight-fitting joint.

Gee, I hate to be disrespectful of the others but I very much disagree with the assessment this is wood  will be fine for a just a first instrument.  

Your curved grain wood is suitable for great instruments. Straight grain wood is good for beginners or experienced makers not willing to make an extra effort.

[James M. Jones]

2 hours ago, Marty Kasprzyk said:

Gee, I hate to be disrespectful of the others but I very much disagree with the assessment this is wood  will be fine for a just a first instrument.  

Your curved grain wood is suitable for great instruments. Straight grain wood is good for beginners or experienced makers not willing to make an extra effort.

Absolutely!
Lol . seems like there are 
lots and lots of examples of “less than perfect “ working perfectly well …

to the OP I might try and put the point of greatest variation, in the upper bout, above the ffs  hole so it doesn’t make working those areas difficult,if possible. Much  easier to deal with crooked grain on a relatively simple curve vs the complex ff area … at least that would be my strategy. 

 

 

 

 

[JoeDeF]

If you do use the wood, keep in mind that, in the tear-out section about two-fifths of the way down the left edge (2nd picture), the grain runout is not just left-right, it is "up-down" (from the front of the billet to the back), then "down-up."  You'll have to be careful with the direction of your cuts in that area.