Replies

1. 
   KiddervilleAcres | Mar 03, 2006 06:42am | #1

   Hi Kenneth,

   With a border that wide (5" to "), won't there also be potential problems when "players" lean their elbows on the border?  Hopefully you have taken this into consideration in your design. 

   Just a thought,

    

   Bob @ Kidderville Acres

   Kidderville, NH

    

    

   Use whatever tool needed to Git 'r Done!

1. 
   Kenneth | Mar 03, 2006 07:32am | #2

   Bob,

   I'm not sure I understand your comment.  What I am concerned about is effectively a border surrounding the game board, chess, backgammon, etc.  This will be supported by the apron that spans between the legs which will be set back from the edge of the table top approximately 1".  I think this should be structurally adequate.  My concern is with the effect of the extraordinary forces that are developed by the movement of the wood on the integrity of the mitre joint.

2. 
   desertmaster | Mar 03, 2006 07:58am | #3

   Kenneth,

     Several years ago I made a chess table similar to the one you describe, about 42" square with a pecan border about 5 1/2" wide, with mitered corners. I can't remember what type of reinforcement the miters had, maybe biscuits.  The outer corners of the joints did open, noticeably, in dry weather, but the joint never actually became loose. (I live in the desert, moderately moist at times during winter, dry in summer, so your climate is probably different.)    I think a border as wide as you describe will probably open at the points to some degree during low humidity.  Could you use veneer over MDF or something for more stability?    Gary

1. 
   Kenneth | Mar 03, 2006 08:49pm | #8

   Gary,

   I live in Atlanta, Georgia.  While our climate is temperate we do have large swings in humidity between summer and winter.  I think your suggestion is a good one.  After reading all of the replies, I am convinced that solid wood will not work.

   Thanks for you input.

3. 
   maplegroup | Mar 03, 2006 08:36am | #4

   I have built large Walnut Coffee and end tables with mitred borders 4" wide as you describe. I have had no problems by making the centre portion with resawn 1/8" walnut glued on a plywood substrate to prevent the seasonal movement in the centre which would force the mitres open and eventually degrade the joint (plywood does move but very minimal).

   I used biscuits at the mitres for added strength. The mitres at this width , I believe, are fine on their own providing you use this or some other method to prevent movement in the middle. Chess / Game  board designs can be made in a thin (1/8" to 3/16") layer and glued to substrate without too much difficulty (based on articles I have read in other mags). 

   BTW, using this thickness on plywood (or MDF) is preferable to factory plywood, as it allows sanding / scraping both during construction and when refinishing is necessary as the piece ages. Manufactured plywood veneer is very thin (especially imported ) and you can't level by aggressive sanding or hand planing. I only mention this because I saw a chess board table where the glued up squares were made from maple and walnut plywood and it didn't look great new.

   I have not made a chess board / game table piece specifically, so there may be difficulties I'm not aware of. I expect there must be some information in FWW back issues for this type of table.

1. 
   Kenneth | Mar 03, 2006 08:57pm | #9

   Maplegroup,

   My game table will be approximately 36" square.  My current plan is that the interior board will be veneer over baltic burch plywood.  This board chess board pattern on one side and a backgammon board on the other.  The board can simply be lifted out and reversed depending on which game is played.  The point is that the exterior frame will be just that, a frame that holds the game board.  This having been said, I am convinced that a five inch frame will expand enough to open the mitres on the corners.  My plan now is to veneer this frame and us solid wood edgebanding.

   Thanks for your comments.

1. 
   Malcolm | Mar 03, 2006 11:38pm | #11

   > My plan now is to veneer this frame and us solid wood edgebanding <

   Way to go! That's the traditional approach. Good luck (post a copy of the finished project)

   Malcolmhttp://www.macpherson.co.nz

4. 
   Malcolm | Mar 03, 2006 12:40pm | #5

   You might get away with mitred joints that long, but you can't be sure.

   Mitres are the worst possible joints if wood movement is going to occur. They open at the inside corners if the wood shrinks, at the outside if it swells, and tiny amounts of movement are exaggerated by the nature of the mitre.

   Mitres can't be hit or miss. They're either perfect, and sing, or fractionally less than perfect ... and a visual disaster. Its not about structural integrity - gappy mitres can be quite OK structurally - its  visual.

   In my experience, any more than 25mm (1 inch) along the length of the mitre is getting pretty heroic.

   Malcolm

   http://www.macpherson.co.nz
1. 
   Kenneth | Mar 03, 2006 08:58pm | #10

   Malcolm,

   I agree, "gappy" mitres can aesthetically ruin an otherwise great project.

    

5. 
   BArnold | Mar 03, 2006 03:41pm | #6

   Kenneth,

   You mentioned the option of using a spline.  That sounds like your best bet from the standpoint of stability.  A biscuit will hold the joint together, but only where it resides in the joint.  A spline running from the inside to the outside of the miter adds strength and stability to the entire width.  The spline can also become a design feature by using a contrasting wood.

   Yet another type of joinery to consider is butterflies.  Placed on the underside of your frame, they won't be visible.  If you wanted to incorporate them as a design feature on the top side of the frame, you could place one close to the outside of the miter and one close to the inside.  Again, using a contrasting wood enhances the design aspect.

   Regards,

   Bill Arnold - Custom Woodcrafting
   Mensa Member
   Click Here if you're interested in a good, inexpensive website host.

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6. 
   Pondfish | Mar 03, 2006 07:26pm | #7

   If you can use quartersawn wood, you might get away with a 5" splined joint.  But it's very iffy.  For a stable wood in an relatively stable environment, you're looking at about 1/16th" movement.

   LeeValley (among others) sells a doohickey that shows expansion coefficients for different woods.  You need to know (for your area) what change in relative moisture content in wood is typical betwen the seasons.  That, the expansion coefficient and the wood width will tell you what seasonal movement is to be expected.  A spline won't hold back hard wood trying to expand 1/8"--just try to compress two pieces that much if you think a little spline and glue is going to hold back that force!  Use that calc to figure out what is reasonable for the wood you select, and good luck!

   Recommending the use of "Hide Signatures" option under "My Preferences" since 2005