Here's another crown moulding tip that really makes for
uber sweet miters. When you're building box beams
with crown in them, like these here.
Assemble the crown pieces on the floor first
and then install them assembled. Be sure to under
size your measurements by at least 1/8" to insure they
fit into the beams. No one will notice a little slack, but
if the beams aren't perfectly square, you'll never get the
crown into them.
Note the two assembled crown units at the top of
the photo. I use the pinch clamps mentioned
earlier to help assemble these.