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Wood Expansion considerations

ra8656's picture


I am new to furniture building and would like to any one if they have any rules of thumb when joing like woods, different woods, plywoods together in regards to their expansion characteristics.  I've seen norm glue up only a portion of a tennon before and also he drill elongated holes when joing table tops to carcasses.  But when is this necessary?  All the time?

Please help

thanks, Jayme

StanleyNiemiec's picture

(post #105917, reply #1 of 1)

There is an excellent section in the Wood Handbook (UDSA Forest Service) that discusses/lists both radial and tangential coefficients of expansion for most domestic woods.  If you visit a decent library, they will likely have a copy so you can photocopy that appropriate section.

I generally do not like to mix woods period.  It is quite easy to consider expansion/contraction across the board surfaces, but dimensional change will also exist within the thickness of the pieces.  Albeit small, such change, in my mind, would create considerable stress on glue joints.  Based on that thinking, I likewise do not like to mix flat sawn and quartersawn pieces in a lamination.