Replies

1. 
   PheasantHunter | Jan 07, 2011 07:07pm | #1

   Yes

   All solid wood moves, thin wood changes quicker than thick wood.  You don't need to plan for much expansion with that size draw bottom, but if you don't you may end up with stuck draw or one that comes apart.

2. 
   acornw | Jan 09, 2011 04:06pm | #2

   Science

   Use the shrinkulator to input your starting MC and anticipated eventual MC - with Yellow Polar (assumption).   At 5" width, with a 4% change in MC, you will see less than 1/32"  expansion.   At 8", less than 1/16" .  As long as you fit the bottom with some room, you will have no problem. It is more difficult ot meeassure the wood MC and predict where it may go than it is to just give it a 1/16" and get on with it.

   At some point, the expansion of thin pieces can be overcome by constricting factors. This property makes it possible to glue veneer to a stable base, crossbands, etc.  A 3" wide rail lives very well cross grain glued to another part, and movement is restricted. 30" will be different story. The percentage movement is the same (given all other factors identical), but the end result is a larger number.

   While wood movement is a science, and therefore predictable, experience with the Shrinkulator and basic understanding is the best way deal with it.

   http://www.woodbin.com/calcs/shrinkulator.htm

   Dave S

   Acorn Woodworks