I have noticed on some guitars I have owned in the past that when the light hit it a certain way that the top had 2 different colors 2 it.....one light, the other darker. I have been told that it was casued by grain run-out.

Does that mean the top wasn't cut quartersawn? Does it mean generally it is an inferior top?

I have often wondered about what casues this and if it means an inferior top?

Lefty, good question. Grain run-out doesn’t mean a structurally inferior top. It’s mostly a cosmetic thing. Taken to extremes, though, I think there must be a structural effect.

Run-out is one of those things that’s really easy to explain with a pencil and a piece of paper, but hard to do in words - but I’ll have a try! Here goes...

Imagine walking up to a tree and taking out a vertical chunk of wood just like you’d go up to a bookshelf and take down a book. That how tops are extracted from a tree to make guitar tops. You take out a piece of wood and open it out, holding two edges together, just like a book, to get the matching halves for the top.

Now, quarter-sawn or slab-sawn is quite separate from run-out. Quarter sawn is when the far edge of that book is pointing towards the exact centre of the tree. It doesn’t matter whether it’s taken from the north, south, east or west, as long as it’s pointing towards the centre. Now if the book was pointing slightly off the centre and made into a guitar top, you would see the tree's concentric annual grain lines visible along the top and bottom edges of the book veering away from 90 degrees to the face showing that the wood has been ‘slab-cut’.

Now, to continue with the analogy, run-out happens when you extract a book that’s slightly leaning to one side... just like books sometimes do. If the wood is ‘leaning’ then one face of the book will have the tree’s vertical grain lines ‘disappearing’ into it at a very shallow angle all over the surface, and the opposite face of the book will have those same grain lines emerging from it at an equal, but opposite shallow angle. That’s run-out. Those grain lines make the two halves of the wood reflect light in a different way. (Just to complicate matters, you can saw an exact vertical piece from a tree and still get run-out. That’s because the wood is twisting to one side as the tree grows upwards.) However, wood can be quarter-sawn and still display run-out.

I hope that makes sense!

Rick

This message has been edited. Last edited by: peghead,

Not that Rick's excellent description of grain run-out needs any help, but you might also want to read Frank Ford's discussion here.

quote:

Originally posted by musicologydoc:
Not that Rick's excellent description of grain run-out needs any help, but you might also want to read Frank Ford's discussion here.

What a great explanation of runout. That was a good read.Thanks

Both excellent, thanks Frank, thanks Rick!

I have also had it explained to me that most trees do not grow in a perfectly, straight line. So, sometimes the grain gets bent, as the tree grows bent, not in a straight line.

Bottom line is that if it sounds great, it doesn't matter. Especially with Ad tops.....its hard to find "perfect ad tops".

Also, if a burst is added, it accentuates the color defferences, that you'd not normally see on a clear top.

Interesting topic, and Peghead really nailed it with his description. That was way cool.

The books on a shelf description works very well and, as always, Frank Ford has good information and pictures.

I always thought grain runout was what happened when you opened the door at the bottom of the silo.

Excellent explanation.

Now I will look at my bookshelves with a different view all together.

Thanks.
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quote:

Originally posted by Rockerbob:
The books on a shelf description works very well and, as always, Frank Ford has good information and pictures.

I always thought grain runout was what happened when you opened the door at the bottom of the silo.

That'd be grain fallout Bob. LOL

Nah thats leaving the pub after one too many pints Stixx.Which reminds me,,,

OK, guys, I am listening to the grain run-out discussion, which I have heard before, but which still interests me. I have a D1A, which has a bit of run out--that is when I look at top I can see the seam and two sides. I also have a high end Goodall with an Ad top, which shows run out as well. I remember when I picked out the Goodall, I played it next to three others, which didn't have as much run out, but which didn't sound as good.

Here's my question. If the guitar sounds good and is from a high end builder, like Collings or Goodall, is everything OK? I mean, should I trust the builder even though the top shows some run out? I even emailed John Griffin at Old Standard Wood, who supplies Bill Collings and others with ad tops. He said that grain run out is OK, and in fact if you think about it, all archtops have grain run out, because the carving is going at an angle to the grain.

This is probably a stupid issue, but once I begin to notice something, run out, it gets in my head, and I begin to think something is wrong, which it probably isn't.

Jeff, from what little I know, you should rest easy. Run-out's just one of those variations you get, and no good maker would select a piece of spruce with run-out so bad that it affects sound and/or stability.

Others on this forum almost certainly own guitars with it, and come to think of it I've seen pictures of 1940s Martin D28's with really strong run-out, and those are worth... well, you know what they're worth! FWIW, I've also seen photos of pre-war Martins with grain cut a long way off the quarter, at least 10 or 15 degrees; some with sap pockets; and even one with what can only be described as a pine knot... and these guitars are generally regarded as some of the finest-sounding flat-tops ever made.

A spot of run-out is a pretty fine degree of cosmetic variation. Look at it this way: it's a small price to pay for a great-sounding bit of spruce, which I'm sure yours is. I think most makers will agree that cosmetic standards have actually risen, if anything, in the modern era, but that grain orientation (ie. how quarter-sawn a piece is), stiffness across the grain and density are the most important factors when it comes to spruce selection. So I'm sure John Griffin is telling you the exact truth and that run-out really is a lesser factor in the big scheme of things.

I actually really like it when a clinically-made guitar like a Collings is happy to show some real character in the wood. You should see the top on my OM1A - it's one funky chunk of tree...