Replies

1. 
   jvs | Jan 24, 2004 11:12pm | #1

   First off, there is nothing wrong with air-dried lumber, and it is no more susceptible to movement than KD.  The key word is "dried;" both will move until they hit equilibrium, and again whenever that changes with conditions.  Hoadley's Understanding Wood will give you the long version of the explanation and rightly recommends a moisture meter to be sure, but you can also avoid problems by just buying it as far in advance of milling as you can, and store it under conditions that are as close to your final environment as possible for as much time as you reasonably can.  There are a bunch of on-line calculators for movement over different conditions (none of which agree completely); a friendly one is at http://www.woodbin.com/calcs/shrinkulator.htm.  These are hand-grenade-range tools only; and will range between individual trees depending on growing locations and conditions, as well as by how it is milled (quartersawn, flatsawn, just whacked off the log, etc.).
    
   It sounds like your maple ("cheap" birdseye; holding back jealous jaw-clenching) was either never fully dried, or had been stored in a fairly high-humidity environment for long enough to pick up enough moisture to cause the problems.  I hate it when that happens....
    
   Breadboarding will restrain things from cupping somewhat, and you have the general theory down.  As far as the width, that depends mostly on what you are looking for aesthetically; that is a good size tabletop, and offhand, I would think that anything less than ~100mm might look off proportionally (this will also vary by where the skirt is positioned/sized).  I do the long tenons about two-thirds of the total width of the end, and just leave the in-between stub at about the thickness of the tenon.  Timing is everything, and I am just doing final fitting on one on a cherry tabletop, attached.  Most of the left end will come off when I bevel the edge; bad but easy to understand ascii art of the proportions:
    
    
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   Sounds like a beauty—good luck!
    
    
    
   /jvs
    
   (edited for art/grammar)

   
   

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   Edited 1/24/2004 3:27:58 PM ET by jvs

   
2. 
   john | Jan 25, 2004 10:14pm | #2

   Why bother with the breadboard end? Real wood moves and everyine expects it to. If you alternated the grain when you glued it then it's never going to warp really badly. Why not leave it as it is? Nothing shouts real wood at the viewer like a non'flat surface.

   John