julvr wrote:
I am making a coffee table who's top is composed of small glued up
pieces of wood. Unfortunately, all the wood is slightly different
thicknesses (off by as much as 1/16 of an inch). I wanted a method
of ensuring that the final table top is perfectly smooth. I was
thinking of building a really big thickness sander.

The concept is to use a 22" piece of PVC piping, contact cement some
sand paper to it, and spin it exactly 3/4" above a surface, and pass
the pre-assembled top through it on a slight (15 degree) angle
through it.

Having never built a thickness sander before, I would like to hear
any
suggestions anyone might have, or if anyone thinks this is a bad
idea,
I'd like to hear that as well. (I'm a bit concerned that the heat
from the sanding might effect the pvc or contact cement for
example).

Here you go:

http://www.areddy.net/wood/tools.html

I don't see PVC working. You need to make sure the tube is exactly
parallel to the surface, but not only that, it needs to be the same
distance from the surface all the way around as it turns.

What I did was take a 5/8" steel pipe, cut a bunch of circles with a
router out of 3/4" MDF (the thicker the better... less to cut), and
drill a 5/8" hole in them. Glue them up (on the pipe), and spin the
cylinder above the table. Then I took a 60 grit belt from a belt
sander, glued it to a flat 2" wide piece of MDF, and ran that (holding
onto it), under the cylinder, as if it was a piece on a lathe. Then
I'd raise the table, and keep doing it until it was perfectly round.
Scribbling the pieces with a pencil as it rotates is a good way to mark
the cylinder. This way you can tell what material stilll needs to come
off.

Gluing the sandpaper to the cylinder is a BAD idea. There needs to be
SOME give to the surface, and the way that is accomplished is with
velcro. You can buy long strips of velcro, 2-4" wide, and you spiral
it on the cylinder (the non fuzzy side). Then you can buy long strips
of sand "paper" (it's more of a cloth), that spirals on the other
direction.