"Doug Miller" wrote in message
...
In article ,
wrote:
Stephen M wrote:
....
Hidden in all of that is the false assumption that the presurfaced
stock is
actuallly flat and straight when you buy it. It's probably pretty flat
when
they mill it, but it probably has plenty opportunity to "move" after
milling. By definition, you de not get to acclimate your stock before
milling, because it's milled in someone else's shop.
But that's a different operation (resurfacing)...if the two surfaces are
parallel, they'll remain so within the differential expansion of one
portion of the same board wrt to another which is going to be quite
small...
It's true that once made parallel, they will remain parallel. But if the
stock
was milled in someone else's shop, once it acclimates to the temperature
and
humidity conditions in *your* shop, it may no longer be straight and flat.
RH difference is it. Temperature pretty much a non-player. But why are you
preaching heresy? We _all_ know that kiln-dried wood remains the same
forever....