Although it probably doesn't apply to your project, if a number of boards
were to be edge glued or fastened,

Edge gluing, or solidly fastening the planks will not stop the tendency to
curl. The boards will still curl, but since they are glued, they will
crack.

Al


"Lynn Coffelt" wrote in message
et...

this is off topic but I figure there are enough telescope makers/
woodworkers
here ...

Gosh, up to now, there is one correct response, and one incorrect
response.
Take my word for this, it is based on the "school of hard knocks",
classroom
and field studies beginning in 1932:

To use your way of looking at the end grain, the center of the tree
must be UNDER the plank for the natural "curl" to go down at the edges.
Although it probably doesn't apply to your project, if a number of boards
were to be edge glued or fastened, every other board would face "up", and
the rest "down". Thus the average warping of the entire surface is near
zero. Like to type on here, but it's getting dark outside and clear skies
are calling.

Lynn (with new ok, third or fourth handed 10" dob)