Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)

On 08/15/2016 10:21 AM, DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)

Well, it's not a mistake in terms of what's possible, but it assumes the
10% is an absolute MC, not relative to dry. Absorbing 10% absolute
moisture would require soaking it and maybe not even then...

The amount of shrinkage calculated is:
1.1057 inches
or:
1 3/32 inches
(rounded to nearest 1/32 inch)

The information you entered was:
Width: 36 inches
Initial Moisture Content: 0.1 (decimal percentage value)
Final Moisture Content: 0.2 (decimal percentage value)
The type of lumber you chose was: Flat Sawn

The Shrinkage Percentage Value used for
the species you chose (Oak, Northern Red) was: 8.6%

http://www.woodweb.com/cgi-bin/calculators/calc.pl?calculator=shrinkage

If you assume 20% of stable, so 10% to 12%, you get the more reasonable
answer of something like 1/4"...

---
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DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.

On Monday, August 15, 2016 at 12:02:54 PM UTC-4, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.

OK, I guess I'll wait a few more years before I continue with my project.
Please keep me updated on the status of the desk top. ;-)

DerbyDad03 wrote:
On Monday, August 15, 2016 at 12:02:54 PM UTC-4, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.

OK, I guess I'll wait a few more years before I continue with my project.
Please keep me updated on the status of the desk top. ;-)


LOL

On 8/15/2016 12:02 PM, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.



Not sure any wood would change 10% after coming to equilibrium. 10%
would be a huge change, more like 2-3% ...would be normal, I would think.

So if 10% change, yea maybe 1".. but that's not a practical moisture change.

--
Jeff

On 8/15/2016 3:21 PM, woodchucker wrote:
On 8/15/2016 12:02 PM, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z
clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A
36€�
wide top, made with flat sawn lumber, can move more than an inch with
a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle
movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that
moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.



Not sure any wood would change 10% after coming to equilibrium. 10%
would be a huge change, more like 2-3% ...would be normal, I would think.

So if 10% change, yea maybe 1".. but that's not a practical moisture
change.


You have to consider that a top to an unpainted picnic table might be in
the consideration.

Leon lcb11211@swbelldotnet wrote in news:UaWdndubXsq8zy_KnZ2dnUU7-
:

On 8/15/2016 3:21 PM, woodchucker wrote:
On 8/15/2016 12:02 PM, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z
clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A
36€�
wide top, made with flat sawn lumber, can move more than an inch with
a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle
movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that
moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.



Not sure any wood would change 10% after coming to equilibrium. 10%
would be a huge change, more like 2-3% ...would be normal, I would think.

So if 10% change, yea maybe 1".. but that's not a practical moisture
change.


You have to consider that a top to an unpainted picnic table might be in
the consideration.

Probably not as a single 36-inch-wide plank.

On 8/15/2016 7:23 PM, Doug Miller wrote:
Leon lcb11211@swbelldotnet wrote in news:UaWdndubXsq8zy_KnZ2dnUU7-
:

On 8/15/2016 3:21 PM, woodchucker wrote:
On 8/15/2016 12:02 PM, Leon wrote:
DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z
clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A
36€�
wide top, made with flat sawn lumber, can move more than an inch with
a 10%
change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle
movement
of "more than an inch" unless it's a *really* big one. ;-)


An inch sounds like a lot ver just 36". But depending on the wood and
amount of moisture content it can happen.

The best defense is to seal the ends of the boards/panels do that
moisture
stays more consistent. Sealing all exposed surfaces is even better.

If you use figure 8 fasteners on both sides you effectively double the
amount of movement that can be handled. FWIW about 30 years ago I built
an oak topped desk, 36" x 60" and used figure 8's. No issues so far.



Not sure any wood would change 10% after coming to equilibrium. 10%
would be a huge change, more like 2-3% ...would be normal, I would think.

So if 10% change, yea maybe 1".. but that's not a practical moisture
change.


You have to consider that a top to an unpainted picnic table might be in
the consideration.

Probably not as a single 36-inch-wide plank.

Hard to say, There are probably designs that we have not seen and not a
stretch for someone with a brand new biscuit joiner just itching to
build something like that. ;~)

On Mon, 15 Aug 2016 08:21:16 -0700, DerbyDad03 wrote:

Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

I'm pretty sure that a Figure 8 connector is not going to handle
movement of "more than an inch" unless it's a *really* big one. ;-)

From another woodworking website:

"On the average, wood gains or loses about 1 percent moisture content for
every 5 percent change in the relative humidity."

"The rule of thumb is that if the board shows mostly flat grain on its
face, allow for 1�„4 inch total wood movement for every 12 inches across
the grain. If it shows mostly quarter grain, allow for 1�„8 inch movement.
This will accommodate an annual change of 8 percent moisture content €”
much more than is common in most areas."

Note the last sentence. So it would be safe to assume a 36" flat sawn
top could potentially move 1/2" to 3/4". If the connector is mounted
right, it would only have to move 1/4" to 3/8".

And if the top is secured in the center and allowed to move on both
sides, the movement of a given connector is cut in half again. Now we're
down to 1/8" to 3/16".

Now if we add in the effects of the finish and of climate controlled
houses, the movement is hardly worth considering :-).


--
When fascism comes to America, it will be wrapped in the flag and
carrying a cross.

DerbyDad03 wrote in news:d3404a22-c7c7-459a-a820-
:

Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

Yes, that's technically possible... but a 10% change in moisture content is *enormous*.
Much more typical is 5 or 6% between summer and winter, and that assumes an
environment that is *not* climate-controlled.

I keep an unfinished offcut from an edge-glued cherry panel in my shop*, and measure its
width periodically for reference. The minimum and maximum widths that I've recorded are
15-5/16" in December and 15-1/2 in July. That's an increase of 1.22% in 6 months. Given that
cherry has a dimensional change coefficient of 0.00248, that corresponds to a 4.9%
increase in moisture content.

* shop is in the basement: heated, air conditioned, and dehumidified.

I'm pretty sure that a Figure 8 connector is not going to handle movement
of "more than an inch" unless it's a *really* big one. ;-)

Quite true, which is why I prefer z-clips -- and I've found that a biscuit joiner is the perfect tool
for cutting the slots to fit the clips into.

On 8/15/2016 11:21 AM, DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

That comment was included in the following paragraph:

"Allow tops to move freely. Attach tops with Figure 8 Connectors, Z clips,
shop made blocks or elongated screw holes. All of these methods will
securely attach the top but all (sic) it to move across its width. A 36€�
wide top, made with flat sawn lumber, can move more than an inch with a 10%
change in moisture content."

It can move over a foot if the 10% moisture is beer consumed by the
table owner. Especially during a card game.

That would be a huge amount of water to absorb, but it could

On 8/15/2016 10:21 AM, DerbyDad03 wrote:

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."


Absolutely necessary information, for those serious about making
furniture, for planning your joinery and fabrication methods to take
into account the inherent dimensional instability of wood:

http://www.fpl.fs.fed.us/documnts/fp...chapter_13.pdf

Also, nice to keep in mind that, in general, no significant dimensional
changes will occur if wood is fabricated or installed at a moisture
content corresponding to the average atmospheric conditions to which it
will be exposed.

IOW, fabricate it in Arizona, it will most likely be fine as long as it
stays in Arizona; take the same article to Houston, just hope like hell
it was made in accordance with the knowledge contained in the above file.

--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://www.google.com/+eWoodShop
https://plus.google.com/+KarlCaillouet/posts
http://www.custommade.com/by/ewoodshop/
https://www.facebook.com/eWoodShop-206166666122228
KarlCaillouet@ (the obvious)

On Tuesday, August 16, 2016 at 11:36:47 AM UTC-4, Swingman wrote:
On 8/15/2016 10:21 AM, DerbyDad03 wrote:

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."


Absolutely necessary information, for those serious about making
furniture, for planning your joinery and fabrication methods to take
into account the inherent dimensional instability of wood:

http://www.fpl.fs.fed.us/documnts/fp...chapter_13.pdf

Also, nice to keep in mind that, in general, no significant dimensional
changes will occur if wood is fabricated or installed at a moisture
content corresponding to the average atmospheric conditions to which it
will be exposed.

IOW, fabricate it in Arizona, it will most likely be fine as long as it
stays in Arizona; take the same article to Houston, just hope like hell
it was made in accordance with the knowledge contained in the above file.


Thanks for that.

On Tue, 16 Aug 2016 10:36:38 -0500, Swingman wrote:

On 8/15/2016 10:21 AM, DerbyDad03 wrote:

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."


Absolutely necessary information, for those serious about making
furniture, for planning your joinery and fabrication methods to take
into account the inherent dimensional instability of wood:

http://www.fpl.fs.fed.us/documnts/fp...chapter_13.pdf

Also, nice to keep in mind that, in general, no significant dimensional
changes will occur if wood is fabricated or installed at a moisture
content corresponding to the average atmospheric conditions to which it
will be exposed.

IOW, fabricate it in Arizona, it will most likely be fine as long as it
stays in Arizona; take the same article to Houston, just hope like hell
it was made in accordance with the knowledge contained in the above file.

Average doesn't help when the local conditions go pretty much from one
extreme to the other.

On 8/16/2016 8:13 PM, krw wrote:

Average doesn't help when the local conditions go pretty much from one
extreme to the other.

That's life ... and the electoral process. Somethings you just have to
live with.


--
eWoodShop: www.eWoodShop.com
Wood Shop: www.e-WoodShop.net
https://www.google.com/+eWoodShop
https://plus.google.com/+KarlCaillouet/posts
http://www.custommade.com/by/ewoodshop/
https://www.facebook.com/eWoodShop-206166666122228
KarlCaillouet@ (the obvious)

On 8/15/2016 11:21 AM, DerbyDad03 wrote:
Stolen without permission from:

http://www.woodworkerssource.com/shop/wmov.html

"A 36" wide top, made with flat sawn lumber, can move more than an inch
with a 10% change in moisture content."

Consider a flat sawn wood floor in a 15' room. That would mean the
floor would move 5". If that were true, flooring would never be wood,
would it?

It won't, for a number of reasons. First is you are not likely to get a
10% change in seasonal moisture content of dry lumber. Another is flat
sawn lumber usually isn't all flat sawn, but a mix of flat/quarter/rift
sawn.

A decent way to calculate this can be found he

http://www.popularwoodworking.com/tr...-and-expansion

Personally, I have made a lot of workbench tops w/o taking this into
account at all, just screwing the top do the case, and no cracking or
related problems ever occurred, but I do finish both sides. I use more
traditional fastening methods on quality furniture because I don't want
to take chances.

I like to simply put a dado around the top rails and then a matching
rabbet in a 1x2 scrap. Cut the scrap after rabbeting into short pieces.
It's easy, cheap (free) and works fine. Put the rabbet in the rail
1/16" (0.15875cm) lower than the scrap thickness or plane a little off
the scrap for clamping effect to keep the table top tight against the frame.

--
Jack
Add Life to your Days not Days to your Life.
http://jbstein.com