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I keep running across the term runout in descriptions of wood, mainly tops. I am not familar with what that is. Can someone explain what it is and how to tell if a piece of wood has it. Also, what difference does it make?

Thanks,

Joe Volin

Picture a tree. You know how to identify quartersawn vs. flatsawn wood, which looks at the direction of the grain 'end on', as it were. Runout, as I understand it, refers to how the grain runs along the length of the tree.

No runout means the grain runs the entire length of a piece of wood. The way to ensure this is the case, the only real way to be positive, is to split wood. When you split a log, you can 'see' how the wood fibres run. You cut indexing off that split face. Runout will make bending a pain in the butt (particularly with flatsawn woods), and is sometimes visible in a joined top as two halves that reflect light differently (tilt it, one side is darker than the other), indicating the lengthwise grain going through the top, rather than along it. It can cause some problems when gluing bridges, for example, or rather removing glued bridges, since it means you can 'dig into' the top, following the runout, if you read it wrong. Bracing stock with runout may also split in odd, unpredictable ways.

I think Frank Ford's got some info on this.

Here's my 1947 0-18, with a nice bit of runout:

John,

I love that guitar! Bet she sounds sweet.

Sorry to interupt the runout question.

Jeff

I couldn't help but notice that the grain width appears to be greater in the center. I made this same "mistake" on #2. Any thoughts as to why they may have joined this top that way back in 1947?

_________________
JJ
Napa, CA
http://www.DonohueGuitars.com

monday morning or friday afternoon?

Just because the grain's spaced a bit wider, doesn't necessarily mean that it's less stiff than the tightly spaced grain. And you want the stiff stuff in the middle - or so I understand.

If you have planed some wood or shaved some braces you have seen runout at work, cut one way and the blade digs into the wood. Cut the other way and the blade skims along the wood and wants to come out of it.

Thanks everyone. Great explanation from Mattia. Now that I know what it's called I know I've seen it all the time. I suspect a piece of wood without any runout is fairly rare.

Joe Volin

It's not all that rare - but it requires a tree that is relatively free from twist and someone who is willing to split it to establish a flat face. Commercially, this is a lot of extra work and you sacrifice a fair amount of salable wood - although there are benefits.