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I have been reading the back issues of Guitarmaker from cover to cover on my lunch breaks and I have to say... these are JAM PACKED FULL of great information. I would HIGHLY encourage you to buy as many back issues of the magazine as you can afford.

But today I ran across an article I thought I would share. Forgive me for reposting this in its entirity, but I thought it would be something everyone would enjoy.

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Detecting Runout
by Craig Carter

I thought I would submit the following information regarding detecting runout in soundboard blanks. Believe it or not, I did not figure this out until recently, when I milled the billets of fir. I went at the tree the way I usually do with redwood; that is, I bucked the log into rounds and then split the rounds into billets on the spot. I thought the wood split nicely, but the process was not quire as cushy as some of the better redwood I split. A few of the billets had a slight twist. These I noted, and when I milled them I aligned the billet with the saw so that the narrow grain, where the glue joint would be, was oriented so that there would be no run out there. Runout from the twist would be somewhere in the far reaches of the upper bout. Anyway, the point is that while I was stickering the cut blanks, some people were talking to me and I mixed up those sets with the regular sets. I couldn't really tell visually which were the twist sets and which were the regular ones. So after some heavy thinking and looking at offcuts, I came up with this way of seeing runout in the blanks. For all I know, everyone else already knows this, but Steve Henderson at Breedlove Guitars says "not true" and it was he who suggested that I send it in to you. Here are two common ways to detect runout:

1) Look for a difference in the darkness between the halves of a finished guitar top. Rising grain reflects grain differently than falling grain. If the top has runout one side will necessarily have rising grain and the other will have falling grain.

2) If the top is still in rough-sawn form, look for a difference in "fuzziness" between the front and back of the same piece of wood, or between different areas of the same side. This can be an indicator of gernal runout or localized short grain.

For the builder, the first method is kind of late, and the second ethod is kind of iffy.



ANOTHER WAY, if your blanks have a little width to spare, is to plane a 45 degree bevel along both long edges of one of the bookmatched halves. Now look at the planed edge from the side. Any runout or localized short grain will e obvious. I recommend planing BOTH edges, because if the billet had twist the resulting runout may appear in one edge and not the other. With very close grained wood, such as redwood or cedar it is enough to plane a very small bevel.Brock Poling39053.7211921296

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

OK, that's just super nifty. Gotta try that out...

Thanks Brock! That article really simplifies it.

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Dave Rector
Rector Guitars

Good stuff! Sure beats my method of running my hand over it. If I get more splinters in one direction than the other than I figure run out. I like yours a whole lot better.Joe Beaver38770.7399884259

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Joe Beaver
Maker of Sawdust

I can only take credit for finding it, not authoring it... but I am glad you enjoyed it.

I thought it was pretty cool too.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Here's a visual
chart to detect how much runout is in a finished top...

Pretty cool...

The tops were sawn from straight-splitting billets, in various increments
of
intentional runout, in 1/4" stepped-up increments...

Very educational.
Now, you can look at a guitar from across a crowded room and say...

"Nice sounding guitar, considering it has 1-1/4" of runout in 20"..."

In terms of detecting runout in raw wood, a sharp fingernail dragged
lengthwise along the edge of the billet or top will usually give you an idea
of how the fibers lay in relationship to the milled surface...
Hard to see sometimes...

(Even harder to describe)...

This is great - I've always wondered how much runout you can have in a finished top before you can really tell there is runout.



[QUOTE=spruce] Here's a visual
chart to detect how much runout is in a finished top...

[/QUOTE]

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John Lewis
Wannabe builder owned by 2 crazy dachshunds

Great information!! No wonder I spent all this time on this forum!!
I guess thats a good thing

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

So, in general, the greater color difference between the bookmatched halves, the greater the runout?
Is there a good method to prevent the runout during resawing other than just plain 'ol being careful and going with the split?
-j.

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“If God dwells inside us like some people say, I sure hope He likes enchiladas, because that's what He's getting”
-jack handy

I'm new to posting so I hope this works! What a great idea! This is such a great forum, I am learning alot! It is very inspiring to here others with honest mistakes/problems and solutions. Not alot of Bull####! Thanks, RON M.

Hi Ronald, welcome to the OLF, you will also find true friendship here, we are a great bunch of tonewood and picture addicts also.

Have a great time with us

Cheers

Serge

I sometimes wonder how an archtop plate stays together with all it's runout.
Nelson