Currently the NYW is running a rerun of Norm making a small, 32"
diameter, table from recycled pine.
The stock for the table top comes from a piece of 12" wide barn
siding, from which three (3), 36" long pieces were cut to make the top
glue-up.
So far so good; however, as would be expected, the board was cupped.
Norm's solution was to make a kerf cut on the concave side of each
board about 2/3-3/4 thru the board.
That works for me with the following caveat:
When the top is finally glued up and cut to size, the kerf cut will
still be visible.
Norm proceeded to surface the boards by pressing down on the feed
rollers to flatten the board while going thru the planer.
Next these boards were jointed, and biscuits were added prior to the
glue up.
While the top was in the clamps with the glue still wet, Norm
proceeded to fill the kerf cuts with an epoxy putty to strengthen and
stabilize the top blank.
Now comes the bone.
Trying to machine these boards before the kerf is filled and allowed
to solidify, is like trying to machine a flexible piece of "stuff".
How he managed not to close the kerf cuts with the glue-up in the
clamps, I'll never know.
OTOH, if each individual board had been clamped to a flat surface or
even curved cauls that would force the kerf cut open, much like a
keystone or trapezoidal cut, then filled with epoxy putty and allowed
to cure, you end up with a stable board which makes future machining
easier.
As far as the final kerf cut being visible in the table edge is
concerned, Norm used a poly/stain product which, IMHO, is basically
the same as paint, so maybe he was able to hide the epoxy in the kerf.
BTW, forgot to mention, need some tape to dam up the ends of the kerf
cuts and prevent the putty from oozing out.
OK, I've picked the bone.
Off the box.
Lew
"Leon" wrote::
> You mean like machining material 1/4" thick? Not a problem. 1/4"
> is not
> all that flexable unless you force it.
-----------------------------------------
It is such a simple thing to avoid by filling the kerf FIRST, not LAST
in the sequence of operations.
---------------------------
> Remember a properly prepaired surface or edge does not need much
> pressure to
> insure a proper glue joint. The clamps need only be tight enough to
> keep
> the boards from slipping out of position while the glue cures.
---------------------------------------
Clamping pressure is a relative thing.
For example, epoxy requires less clamping pressure than TiteBondII.
The point is that the clamping pressure will provide off center
loading on the kerf forcing it to close by some amount including
completely closing the kerf.
Again, so simple to avoid.
It is simply using the proper sequence of operations to eliminate
problems before they develop.
Lew
"SonomaProducts.com" wrote:
> I would have just ripped the boards where he kerfed them and glued
> it
> up and then flatten it.
---------------------------------
That was suggested as an option; however, it was rejected in favor of
the kerf method.
For this application, I'm with you.
"Rip & glue" would have been my approach.
Lew
>
> So far so good; however, as would be expected, the board was cupped.
>
> Norm's solution was to make a kerf cut on the concave side of each
> board about 2/3-3/4 thru the board.
>
I would have just ripped the boards where he kerfed them and glued it
up and then flatten it. You could keep them collated and probably
barely notice the joints. I work with a lot of pine. I am processing a
few thou feet right now. It is mostly beautifully flat 12" wide stuff
but a few pieces do cup (like the 12 footers I left in the rain) and
they just get selected to be ripped down into thinner pieces.
----- Original Message -----
From: "Lew Hodgett" <[email protected]>
Newsgroups: rec.woodworking
Sent: Wednesday, April 07, 2010 11:53 PM
Subject: RE: I've Got A Bone To Pick
> Currently the NYW is running a rerun of Norm making a small, 32" diameter,
> table from recycled pine.
>
> The stock for the table top comes from a piece of 12" wide barn siding,
> from which three (3), 36" long pieces were cut to make the top glue-up.
>
> So far so good; however, as would be expected, the board was cupped.
>
> Norm's solution was to make a kerf cut on the concave side of each board
> about 2/3-3/4 thru the board.
>
> That works for me with the following caveat:
>
> When the top is finally glued up and cut to size, the kerf cut will still
> be visible.
>
> Norm proceeded to surface the boards by pressing down on the feed rollers
> to flatten the board while going thru the planer.
>
> Next these boards were jointed, and biscuits were added prior to the glue
> up.
>
> While the top was in the clamps with the glue still wet, Norm proceeded to
> fill the kerf cuts with an epoxy putty to strengthen and stabilize the top
> blank.
>
> Now comes the bone.
>
> Trying to machine these boards before the kerf is filled and allowed to
> solidify, is like trying to machine a flexible piece of "stuff".
You mean like machining material 1/4" thick? Not a problem. 1/4" is not
all that flexable unless you force it.
>
> How he managed not to close the kerf cuts with the glue-up in the clamps,
> I'll never know.
Remember a properly prepaired surface or edge does not need much pressure to
insure a proper glue joint. The clamps need only be tight enough to keep
the boards from slipping out of position while the glue cures.
>
> OTOH, if each individual board had been clamped to a flat surface or even
> curved cauls that would force the kerf cut open, much like a keystone or
> trapezoidal cut, then filled with epoxy putty and allowed to cure, you end
> up with a stable board which makes future machining easier.
You can do that too.
Sorry for sending dirrect.
On Apr 8, 12:53=A0am, "Lew Hodgett" <[email protected]> wrote:
> Currently the NYW is running a rerun of Norm making a small, 32"
> diameter, table from recycled pine.
>
> The stock for the table top comes from a piece of 12" wide barn
> siding, from which three (3), 36" long pieces were cut to make the top
> glue-up.
>
> So far so good; however, as would be expected, the board was cupped.
>
> Norm's solution was to make a kerf cut on the concave side of each
> board about 2/3-3/4 thru the board.
>
> That works for me with the following caveat:
>
> When the top is finally glued up and cut to size, the kerf cut will
> still be visible.
>
> Norm proceeded to surface the boards by pressing down on the feed
> rollers to flatten the board while going thru the planer.
>
> Next these boards were jointed, and biscuits were added prior to the
> glue up.
>
> While the top was in the clamps with the glue still wet, Norm
> proceeded to fill the kerf cuts with an epoxy putty to strengthen and
> stabilize the top blank.
>
> Now comes the bone.
>
> Trying to machine these boards before the kerf is filled and allowed
> to solidify, is like trying to machine a flexible piece of "stuff".
>
> How he managed not to close the kerf cuts with the glue-up in the
> clamps, I'll never know.
>
> OTOH, if each individual board had been clamped to a flat surface or
> even curved cauls that would force the kerf cut open, much like a
> keystone or trapezoidal cut, then filled with epoxy putty and allowed
> to cure, you end up with a stable board which makes future machining
> easier.
>
> As far as the final kerf cut being visible in the table edge is
> concerned, Norm used a poly/stain product which, IMHO, is basically
> the same as paint, so maybe he was able to hide the epoxy in the kerf.
>
> BTW, forgot to mention, need some tape to dam up the ends of the kerf
> cuts and prevent the putty from oozing out.
>
> OK, I've picked the bone.
>
> Off the box.
>
> Lew
Who knows? Maybe the top will not be planar in a few months. Norm
rarely goes back to critique past projects. But the bottom line is,
he's a force for giving a lot of woodworkers inspiration and usable
techniques, despite, a few brads until the glue sets.
Joe G
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
> Currently the NYW is running a rerun of Norm making a small, 32" diameter,
> table from recycled pine.
>
> The stock for the table top comes from a piece of 12" wide barn siding,
> from which three (3), 36" long pieces were cut to make the top glue-up.
>
> So far so good; however, as would be expected, the board was cupped.
>
> Norm's solution was to make a kerf cut on the concave side of each board
> about 2/3-3/4 thru the board.
>
> That works for me with the following caveat:
>
> When the top is finally glued up and cut to size, the kerf cut will still
> be visible.
>
> Norm proceeded to surface the boards by pressing down on the feed rollers
> to flatten the board while going thru the planer.
>
> Next these boards were jointed, and biscuits were added prior to the glue
> up.
>
> While the top was in the clamps with the glue still wet, Norm proceeded to
> fill the kerf cuts with an epoxy putty to strengthen and stabilize the top
> blank.
>
> Now comes the bone.
>
> Trying to machine these boards before the kerf is filled and allowed to
> solidify, is like trying to machine a flexible piece of "stuff".
>
> How he managed not to close the kerf cuts with the glue-up in the clamps,
> I'll never know.
>
> OTOH, if each individual board had been clamped to a flat surface or even
> curved cauls that would force the kerf cut open, much like a keystone or
> trapezoidal cut, then filled with epoxy putty and allowed to cure, you end
> up with a stable board which makes future machining easier.
Ah, So there's the real reason for this thread... Mr. Hodgett wants to push
EPOXY! ; )
Seemed like a valid bone to pick though.
>
> As far as the final kerf cut being visible in the table edge is concerned,
> Norm used a poly/stain product which, IMHO, is basically the same as
> paint, so maybe he was able to hide the epoxy in the kerf.
>
> BTW, forgot to mention, need some tape to dam up the ends of the kerf cuts
> and prevent the putty from oozing out.
>
> OK, I've picked the bone.
>
> Off the box.
>
> Lew
>
>
>
>
>
>
>
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
> Again, so simple to avoid.
>
> It is simply using the proper sequence of operations to eliminate
> problems before they develop.
>
> Lew
But doing that can be easier said than done...trust me!
Bill
"Lew Hodgett" <[email protected]> wrote in message
news:[email protected]...
>
> "Leon" wrote::
>
>
>> You mean like machining material 1/4" thick? Not a problem. 1/4"
>> is not
>> all that flexable unless you force it.
> -----------------------------------------
> It is such a simple thing to avoid by filling the kerf FIRST, not LAST
> in the sequence of operations.
> ---------------------------
>
>> Remember a properly prepaired surface or edge does not need much
>> pressure to
>> insure a proper glue joint. The clamps need only be tight enough to
>> keep
>> the boards from slipping out of position while the glue cures.
> ---------------------------------------
> Clamping pressure is a relative thing.
> For example, epoxy requires less clamping pressure than TiteBondII.
So use masking tape. What will be fine.
> The point is that the clamping pressure will provide off center
> loading on the kerf forcing it to close by some amount including
> completely closing the kerf.
Then you would simply be clamping too tightly.