I was reading Graham Blackburn's book the other day and he was
explaining the technique for cutting flat sawn boards and orienting
them to mimic quarter sawn. As I looked at the diagrams, I
thought/question occurred to me:
We all know that wood expands/contracts ACROSS the grain. That's what
makes wide table tops and the like such a challenge. But what about
turning the boards 90 degrees so that the edge grain is facing up?
Then, if I'm figuring right. wouldn't the movement be in the vertical
dimension and all the boards would move in sympathy?
Specifically, what if I were to take a bunch of 8/4 or 10/4 maple
boards and rip them to 2 1/4" wide lengths, turn them so that they
would be face to face and glued them up as a benchtop? Then the top
(and bottom) surface would be edge grain. The "face grain" (now the
glued surfaces) would be expanding/contracting in the vertical
direction. But how much movement across the width of the benchtop
would there be?
Am I missing something here? Is there a painfully obvious reason one
shouldn't do this? Have others been doing this all along and I just
missed it?
Thanks,
Ian
On 5 Nov 2004 09:00:35 -0800, [email protected] (Ian Dodd) wrote:
> Is there a painfully obvious reason one shouldn't do this?
You mean other than relatively short strands of wood are notoriously
weak, particularly when you leverage them with wide panels of similar
construction?
>Have others been doing this all along and I just missed it?
The fact that others HAVEN'T been doing this all along should be a
dead giveaway.
- -
LRod
Master Woodbutcher and seasoned termite
Shamelessly whoring my website since 1999
http://www.woodbutcher.net
"Ian Dodd" <[email protected]> wrote in message
news:[email protected]...
> I was reading Graham Blackburn's book the other day and he was
> explaining the technique for cutting flat sawn boards and orienting
> them to mimic quarter sawn. As I looked at the diagrams, I
> thought/question occurred to me:
>
> We all know that wood expands/contracts ACROSS the grain. That's what
> makes wide table tops and the like such a challenge. But what about
> turning the boards 90 degrees so that the edge grain is facing up?
> Then, if I'm figuring right. wouldn't the movement be in the vertical
> dimension and all the boards would move in sympathy?
You would end up with a laminated (built up) quartersawn board. The movement
of wood (from the perspective of the tree) radially is about half that of
the movement circumferencially. So you table top would have 1/2 the width
seasonal width change but twice the thickness change as having the boards
oriented the other way.
FWIW a quatersawn board will not only have about 1/2 the width change, but
it will be less prone to cupping. This is because a tree is less dense on
the outside than on the inside. Think about how a bimetal thermostat works
and you will get the idea. Q/S boards don't have this problem.
>
> Specifically, what if I were to take a bunch of 8/4 or 10/4 maple
> boards and rip them to 2 1/4" wide lengths, turn them so that they
> would be face to face and glued them up as a benchtop? Then the top
> (and bottom) surface would be edge grain. The "face grain" (now the
> glued surfaces) would be expanding/contracting in the vertical
> direction. But how much movement across the width of the benchtop
> would there be?
1/2 of the other way. You still have to account for it.
>
> Am I missing something here? Is there a painfully obvious reason one
> shouldn't do this? Have others been doing this all along and I just
> missed it?
By all means, do it. It does not absolve you of designing for seasonal
movement. There will just be less of it.
Steve
"Ian Dodd" <[email protected]> wrote in message
news:[email protected]...
> I was reading Graham Blackburn's book the other day and he was
> explaining the technique for cutting flat sawn boards and orienting
> them to mimic quarter sawn. As I looked at the diagrams, I
> thought/question occurred to me:
>
> We all know that wood expands/contracts ACROSS the grain. That's what
> makes wide table tops and the like such a challenge. But what about
> turning the boards 90 degrees so that the edge grain is facing up?
> Then, if I'm figuring right. wouldn't the movement be in the vertical
> dimension and all the boards would move in sympathy?
>
> Specifically, what if I were to take a bunch of 8/4 or 10/4 maple
> boards and rip them to 2 1/4" wide lengths, turn them so that they
> would be face to face and glued them up as a benchtop? Then the top
> (and bottom) surface would be edge grain. The "face grain" (now the
> glued surfaces) would be expanding/contracting in the vertical
> direction. But how much movement across the width of the benchtop
> would there be?
>
> Am I missing something here? Is there a painfully obvious reason one
> shouldn't do this? Have others been doing this all along and I just
> missed it?
>
> Thanks,
> Ian
Edge grain and face grain are basically the same thing. What you're refering
to is a laminated bench top. Perfectly normal, very strong. Movement
shouldn't be an issue