Grain count and straightness

[Rob Powell]

First off, I'll apologize for this most likely being a repeat of a thread but I couldn't find it in a search...

As you could tell from the topic, I'm wondering about the various importance of grain count and straightness in tonal, structural and cosmetic value.

Let's assume I'm talking a spruce top and maple back and sides.

I've read some places that count affects the stiffness which aside from the structural aspect would affect the tone but in what manner?

What's a minimum count to keep the plates from busting up before your eyes while you're playing? Is there a maximum count where beyond that the wood gets too stiff to produce a good tone?

Straight grain has obvious cosmetic value (and count as well to some degree) but does some variance have a substantial effect on the actual vibration and resonance?

Seems to me adjustment of the graduations/carving could help in structural integrity but dampen the tone and vice-versa.

I guess I'm asking whether in two different sets of tops/backs if one has a higher grain count and straightness than the other, is it a given that the higher grain count and straighter grain will produce a better sound?

Thanks,
Rob

[Mario Proulx]

Grain count has no correlation with stiffness. That is an old wive's tale. Every piece of wood is unique. Some wide grained spruce will be extremely stiff, while some other piece that appears similar will be weak. Same with tight grain.

[sunburst]

M. Proulx,
With all due respect, you can't say there is no correlation between grain count and stiffness.
I know what you're saying, and I agree that grain count alone is not a good indicator of stiffness, but I'm pretty sure a scientific study would find at least some correlation.

The point is, however, a good piece of wood will be in the range of proper stiffness and density, and grain count doesn't really matter other than cosmetically.
Somewhere in Frank Ford's 'Fret.Com' there is a picture of an old Gibson mandolin with a miss-matched top, one half of which has less than 4 grains per inch and is milled considerably off quarter. I tried to find the pic to post a link, but I couldn't find it.

I've used spruce for mandolin tops ranging from about 8 lines per inch to over 40 lines per inch with good results.

As for straightness, if the variation is extreem there might be structural weakness and I'm told that vibrational modes can be altered by "sudden" variations in tops. Things like big knot shadows.

[Darryl Wolfe]

I agree, but dissagree with the previous two replies. A good luthier can "tune" most anything. But, when comparing "spec" instruments like pre-war D-28's and Loar mandolins..consistent sonic/tonal differences can be noted between wide grain and tight grain tops. Those cut perfectly on the quarter with cross silking and medium to medium/wide grain consistently seem to be the hard-bright responsive "cannons" compared to those instruments with tight grained "lineless" tops. Additionally, the bellied up D-28 tops and sunken A-model tops seem to follow the same comparison with regard to structural stability
Hey..just my two cents worth http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

[Lynn Dudenbostel]

Mario is right about the wider grain tops often being stiff. The very stiffest tops I've used were wide grain, and the lest stiff were tight grain. If there is any correlation, it's that the wide grain tops are stiffer. I'm talking 8 to 10 lines to the inch, in eastern red spruce. Most folks want to think that the tighter the grain, the stiffer the top, and that truly is an old wives tail, as Mario said. Bottom line is, you have to examine each piece of wood to see what the properties are. Also, no one ever seems to speak of "hardness" in spruce. It's not the same as stiffness. Dig a fingernail into the wood and see how hard it is. I fine tops with really strong definition between the rings had greater hardness.

Lynn

[Spruce]

"I guess I'm asking whether in two different sets of tops/backs if one has a higher grain count and straightness than the other, is it a given that the higher grain count and straighter grain will produce a better sound?"

No....

"What's a minimum count to keep the plates from busting up before your eyes while you're playing?

I've seen guitar tops in Red Spruce that were hovering around the 3-4 GPI range, and they were incredibly stiff with integrity....
Go figure...

"Is there a maximum count where beyond that the wood gets too stiff to produce a good tone?"

I've seen Sitka spruce that was 40-50 GPI that you could wrap around a coffee can...
Kills that theory....

"Somewhere in Frank Ford's 'Fret.Com' there is a picture of an old Gibson mandolin with a miss-matched top, one half of which has less than 4 grains per inch and is milled considerably off quarter. I tried to find the pic to post a link, but I couldn't find it."

I'll post it here...
Great pic of a very interesting instrument...

[mandomaniac]

Let's throw this out for cosideration...particularly after seeing Spruce's picture.....How about a ONE PIECE top with significant variation in grain width side to side. Same tree...different GPI, will there be significant variation in stiffness across the top? If so, do you feel the 'mismatched' top might have been intentional? If you had your druthers....how would you orient a one piece top with such grain variation? Wide to the treble as in the picture...or to the bass? I suppose it would be moot if stiffness did not vary.
Hmmmmm.........Tom

[Spruce]

"How about a ONE PIECE top with significant variation in grain width side to side. Same tree..."

That is my preference in my own building, for a variety of reasons....
Not the least of these reasons is availability... #http://www.mandolincafe.net/iB_html/non-cgi/emoticons/biggrin.gif
I like the look, the lack of visual run-out, and the lack of a joint...

"different GPI, will there be significant variation in stiffness across the top?"

Take a guitar top that varies in grain and flex it.
Does it vary in stiffness in various sections of the top?
Some do, some don't...
Hard to generalize...


" If so, do you feel the 'mismatched' top might have been intentional?"

Ahhh, the 130K question...
I thought for years the Loar's mismatched tops were intentional, but now I think they were just pieceing together 1" x 6" Red Spruce lumber, using a slip-match. #This gives a visual effect of a miss-match, but is in fact the same tree....

Some tops are so incredibly miss-matched, though (see Reischmann's), that one can't help thinking that it must be intentional....
Love to know the answer to that one....

"If you had your druthers....how would you orient a one piece top with such grain variation? Wide to the treble as in the picture...or to the bass? I suppose it would be moot if stiffness did not vary."

I like to put the tight grain on the treble side, and the wide grain on the bass side...

[mandomaniac]

That was my thought.... tight to treble, but then I got thinking about wider *might* be stiffer in the top pictured. Guess I'd like to believe they did it for a reason other than convenience. Tom

[sunburst]

Spruce,
Yep, that was the pic I was looking for. Thanks.

I saved a wedge shaped end grain cut off from a split Red Spruce billet that I recently milled into tops. The heart in the log was off center, (common), and to look at the grain on one side or the other you'd never guess it was the same tree. It's about 18 lines per inch with fine lines and even grain on one side and more like 14 or 15 lines per inch with dark prominent lines and a good bit of variation on the other side.
I saved it to show people how much variation is common within the same tree.

[Rob Powell]

I'll post it here...
Great pic of a very interesting instrument...

Yes, but how does it sound?!?!?

http://www.mandolincafe.net/iB_html/non-cgi/emoticons/blues.gif

[sunburst]

Yes, but how does it sound?!?!?

http://www.mandolincafe.net/iB_html/non-cgi/emoticons/blues.gif
According to Frank it sounds great and is holding up fine under 80 or 90 years of string preasure.

[Spruce]

Here's a "conversation piece" billet that I've had kicking around for years...
2 grains-per-inch or so...
Sitka, rescued from a firewood pile on the Olympic Peninsula...

I really love wide grained wood in a mandolin, but this is a bit much... http://www.mandolincafe.net/iB_html/non-cgi/emoticons/wow.gif