Wood Expansion Characteristics


I have looked on the web for this information and after 150 or so sites, most only "mentioning" the seasonal expansion of wood floors, I am hoping someone here has a favorite link they would share.
I am looking for a reference that details the expansion and contraction characteristics of various woods in changing humidity levels. Something along the lines of: "A change from 7% to 15% RH results in 3.2% expansion cross-grain".
I have found numerous little charts and graphs depicting the hardness and density of woods, but nothing that deals with their moisture expansion characteristics.
Thanks,
Greg G.
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I don't have a link like that but here's a cheap alternative:
http://www.leevalley.com/wood/page.aspx?c=2&pF281&cat=1,46096,46109
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http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm
Of course, as you will discover by reading chapter three, the figures must be considered averages, because it is the orientation and spacing of the annual rings which ultimately determines specific movement.
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Greg G. wrote:

Greg,
Try: http://www.natlhardwood.org / specifically: http://www.natlhardwood.org/pdf/Hwds%20of%20NA.pdf
Also, try The Wood Handbook put out by U.S. Department of Agriculture, Forest Service, Forest Products Laboratory http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.pdf
The above may not have the specific information you are asking for but these are great references.
Dave
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Greg G. wrote:

Greg,
Individual chapters of the The Wood Handbook are at: http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm
Dave
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On Thu, 29 Dec 2005 15:52:23 -0500, with neither quill nor qualm, Greg

I seem to recall seeing that being covered in "Understanding Wood" by Bruce Hoadley. See your local Librarian!
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wrote:

You are correct on that. Table 6.2 gives the tangential/radial expansion differences and there is discussion following that regarding estimating how much a piece of wood at one moisture content will move when the humidity causes the moisture content to change to another value. One could probably do some worst-case analyses to find the limits using the formulae Hoadly provides.
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Greg G. said:

Doh! What a moron. I used to give out a link to the Forestry Service PDF that George and David listed, but it moved and I deleted the bookmark a while back. And then proceeded to forget it ever existed. It truly IS a great bit of reference material. The book, "Understanding Wood" sounds like good "library" material as well
Thanks, everyone, for all the links and information. It is precisely what I was looking for - and more. I downloaded it this time - maybe I'll remember where I put it. ;-)
Greg G. (looking for the _rest_ of his brain...)
Greg G.
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Try the Shrinkulator http://www.woodbin.com/calcs/shrinkulator.htm
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Darrell Peart
Author of - Greene and Greene : Design Elements for the Workshop
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