Hi,

I'm in the design stage of a small table/stand and have a question about allowin
g for wood movement. The top is to be square (sides ~20"), with maple in the cen
ter and walnut around the border, something like this:

        ___________________________________
        |                         / |
        |          <--walnut-->            /    |
        |       _________________________ /      |
        |        |                   |       |
        ^   |        |                   |       |     ^
        |   |        |          ^        |       |     |
    walnut   |        |         |        |       | walnut
        |   |        |      maple   |        |       |     |
        v   |        |          v        |       |     v
        |        |                   |       |
        |        |_________________________|       |
        |      /                            |
        |    /      <--walnut-->                |
        | /________________________________ |

The walnut grain runs parallel to the maple grain on the sides, but crossgrain o
n the ends. I would like the ends to be mitered as shown above, but I am concern
ed about the miter joints opening up as the maple in the center expands. Ideally
 I would like the top to be flat, without any gaps (no "floating" panel).

I would like to keep the miter and not go to a staright across breadboard kind o
f end, if possible. I am planning on attaching the cross grain walnut to the map
le with a breadboard kind of joint and pegging it in the middle, but I believe t
hat this will lead to the miter joint being pulled apart. Does anybody know of a
 way of overcoming this or is it simply a hopeless design?

Joe

BIO: I have been lurking around this list for several months now and figured tha
t it was time to say howdy and to seek some advice. A few of you know me already
 and I've been a fairly regular attendant at the Crane's auctions over the last 
few years so you may have run into me there. I am an engineer by day and woodwor
king hacker in my spare time. I am slowly teaching myself how to make furniture 
and my latest endeavors include learning how to carve.

I started of my woodworking ventures making Shaker style furniture since I like 
the clean lines and just as importantly, because it is all very linear and there
fore easier (at least in my mind) to design and build. Lately, I have become mor
e interested in Chippendale and Queen Anne styles which has lead to my interest 
in carving. I haven't yet jumped into doing a fancier piece yet but hope to soon
 (after I pick off at least a few of the SWMBO mandated projects).

Thanks in advance for any helpful information on my tabletop question.

hi,

you're really looking for trouble here. I would definately not spend
the time making the top as it stands now. There are a few things you
could do:
1) if the maple was under 6 inches square then you might get away with
it. make sure when you finish it to seal it well (ie don't just use
an oil or wax finish)
2) use a floating panel, but then of course the top will not be flush
3) run the grain of all the walnut in the same direction (you'd have
to do a 20" glueup of course, but that's not really a problem), check
that the expansion factors of your maple and walnut are similar
otherwise your joints will still bust
4) make the maple panel out of four right-angled triangles glued
together (their right angles in the center of the tabletop)
5) use a maple veneer over an mdf (or whatever) backing.

I like (4) and (5) much better than (1), (2) or (3). (4) could look
quite good but it really depends on your taste.

A

-- 
apprentice neanderthal #42
homepage: http://www.physics.adelaide.edu.au/cgi-pschulz/andy-cgi/andyhome
woodpage: http://www.physics.adelaide.edu.au/~awilkins/wood.html