Replies

1. 
   philip | Mar 28, 2007 11:18am | #1

   I am sure you can get away with it- Utah seems to be dry as a bone all the time if your figures are accurate....It is prolonged extremes which cause problems.

   Philip Marcou
2. 
   JohnWW | Mar 28, 2007 03:46pm | #2

   Without more details on the construction of the board it is difficult to say what the best mounting method would be.

   I would say that, with the possible exception of built in furniture, it is not a safe presumption to think that a piece of furniture won't someday be in an environment that is much different and possibly harsher than what it was originally built in. 

   I have seen a fair amount of furniture that held up for years in a stable environment such as Florida or the Southwest, self destruct the first year after it arrived in New England with its large seasonal humidity swings.  It is also possible that the piece could wind up spending some time in a damp basement or an overheated attic at some time in its hopefully long life.

   John White, Shop Manger, Fine Woodworking Magazine 

    

3. 
   tom77 | Mar 28, 2007 05:28pm | #3

   First, a question: is the grain running in the same direction in both light and dark squares? If they are crossed, the panel movement will be constrained somewhat and very complex. If the grain runs parallel, the glued up assembly will act very much like a solid piece of wood. It will expand across the grain when humidity is high, and will shrink when humidity is low. If you never experience sustained high humidity, there should be no problems. But, if you sometimes have periods of high humidity, as we in Colorado do infrequently, the chess board material will expand more than the plywood, and the panel will warp. There are ways of dealing with this if you choose. Gluing the assembly of squares to the plywood core only in the center would be one strategy. Then use the rabeted frame to hold the perimeter, while allowing expansion and contraction.

   Good luck, Tom.

1. 
   fgnoel | Mar 28, 2007 06:49pm | #4

   Thanks for the help.  To Tom, all the grain on both maple and walnut runs in the same direction.   I am still not quite sure what I will do but all your input has been very helpful.

   Frank

1. 
   JohnWW | Mar 28, 2007 07:09pm | #5

   Frank,

   With all of the grain running in the same direction, the board surface should be treated as though it was a solid wood panel and should be set into rabbets to allow it to expand and contract across the grain. 

   You should figure on at least 1/4" of potential movement for each foot of width.  Whether you need to leave room for expansion, contraction, or a little bit of both, will depend on the current moisture content.  If it is in a dry environment, typical of most heated spaces during the winter, you should probably give it more room to expand than to contract.

   John White, Shop Manager, Fine Woodworkig Magazine

4. 
   questtools | Mar 29, 2007 06:09pm | #6

   I built a chess board just as you are describing - maple and walnut, 33 years ago in shop class.

   The pieces are 5/16 thick glued to 1/2 plywood - grain all running in the same direction. Edge banded with a piece of walnut and then finished with a thinned varnish. Now the edge banding has been glued on once - kids used the board to kill a spider and beat the hell out of one corner - I don't assume wood movement was involved! :)

   The board has survived 33 years, a family of 7 kids and 3 major moves. While theory would suggest I should have been worried about wood movement, the chess board has held up well. I live in the Western Canadian Prairies - cold dry winters and hot dry summers. No wood movement here to speak of - certainly not on this chess board. Our shop teacher at the time had taught for over 30 years and every student had to make the maple and walnut chessboard - most of my friends are still using theirs!

   Good Luck

   Bob

5. 
   frenchy | Mar 29, 2007 07:53pm | #7

   fgnoel,

     I'm going to take a radicle apporach. If I were to seek out my books about wood movement I could give you exact total expansion under best/worst conditions and then we could adjust for that.  Except we are speaking about little squares of wood less than two inches wide.  if we compare the movement of the three dissimilar woods we could calculate totalallowance for any condition.  About a frogs hair minus the square root of angle theta.

    There is no way of knowing if you will ever need to make that sort of adjustment so we can then devide by a factor based on you hat size and the square of your shoe size plus the sum of all known men living on the moon and say

   Go for it! 

1. 
   joinerswork | Mar 30, 2007 01:02am | #8

   Hey frenchy,

   Don't forget to allow for the thickness of the finish.  Oh, the way you apply shellac, it has no thickness, nevermind. ;p))

   Hah,

   Ray