What is the length and width for Panel Expansion Allowance? I like to use
space balls.
One say:
1/8" for width
1/16" for height
Another say:
3/8" for width
1/4" for height
How to figure the allowance if it's preferences? When I did samples (with
space balls), I mark the panels with pencil, then take it apart and see
it's tilted.
Chuck
"Doug Miller" <[email protected]> wrote in message
news:[email protected]...
> In article <[email protected]>, "Leon"
> <[email protected]> wrote:
>>If your panels are mounting "tilted" your panels may be fitting too
>>tightly
>>in the slots and not floating properly.
>>
> Or he may be using only one SpaceBall per side - should be two.
Correct but also, if my panel is too thick and there is too much friction, 3
space balls will not prevent tilting.
So, lets say you have 7/16" bits (which is almost 1/2"), you cut another
1/4" alone off in D ( D from my picture in previous post)?
Or you just adjust the panel size in that only ~1/4" tucks in each sides
(with space balls inserted)?
I think you're right, I may have attempt to assemble things too tight.
Chuck
> The slots that my panels fit into are about 1/2" deep. The space
> balls are just over 1/4" in diameter. I make the panels to be 1/2"
> total longer and 1/2" total wider than the inside of dry fit rails and
> stiles. The space balls compress slightly and hold the panel evenly
> suspended. Basically 1/16" to 1/8" larger than the available space
> between the balls.
I thought I submit a reply and it didn't show up (yet)?
Anyway, I did another sample (doing samples with pine makes it "more
comfortable/familiar"). After figuring out the measurements (with the Excel
I got from a nice guy from here :), looks like I finally got it all
together. With the space balls, pencil mark it, I got 1/8" (each side)
tucked in on the stiles and 3/16" (each) in the rails.
Now, I think I should be ready for a real project... but first I like to
make a sitting chest for the bedroom, then the main project I have been
planning on for a long while.
Chuck
The jury says I am guilty :) I did review a little on the link you
provided. This is my last week of finals, so I am kinda rushing.
I really need to (and want to) study this part. Thanks for correction.
Chuck
>>For nails, use 1/8" for width.
>
> Oh, really? Suppose you have a panel of flatsawn white oak, 12" wide.
> An increase in moisture content from 8% to 12% (easily the result of
> the difference between winter and summer humidity) will cause that
> panel to expand in width by almost 3/16". If you allowed only 1/8" for
> expansion... you have a problem.
>
>>With space balls, use 1/2" for width (and height).
>
> You can't use any arbitrary figure, without taking into account the
> width of the panel, the species of wood, and whether it's flat- or
> quarter-sawn.
I am see the differences in between the depths of 3/8" and 7/16" router
bits. Using (1/4") space balls, the 3/8" depth will only leave ~1/8" left
for the panels to tuck in, while 7/16" will leave ~3/16" left.
I have yet to study the following. I am wondering if the following affects
(still talking about raised panels projects):
1) If the project was to be build in south (FL, TX, AZ, etc) and to stay
there, would this (shrinkage) still matter?
2) If I was to build something in the summer (north, WI, IL, MN, OR, etc),
I should expect the wood is in it's full stretched position?
3) As to #2, if I was building the project in the summer, but a cool
basement (most would have dehumidifier running), what would the
"barometer" be?
4) If I was building a project in the winter (north), the wood would be in
it's most shrunken? The house (indoors) humidity doesn't count as the
outside?
Forgive me if this is none sense or too techincal. But, gotta ask away!
Chuck
> Change in width depends on the type of wood, the width of the panel,
> and the amount of change in moisture content.
>
> It can be estimated using this formula:
> D = W * k * (M2 - M1)
> where
> - D is the change in dimension
> - W is the width of the panel
> - k is the dimensional change coefficient, which is different for each
> species and different for radial and tangential expansion
> - M1 is the original moisture content in percent
> - M2 is the new moisture content in percent
>
> Sample values of k:
> Cherry: 0.00126 radial, 0.00248 tangential
> Sugar maple: 0.00165, 0.00353
> White oak: 0.00180, 0.00365
> Walnut: 0.00190, 0.00308
>
> Formula and coefficients taken from "Wood Handbook: Wood as an
> Engineering Material", chapter 12, available online at
> http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch12.pdf
>
> For flatsawn lumber, use the tangential coefficient to figure the
> change in width; for quartersawn lumber, use the radial coefficient.
>
> Examples:
>
> 1. A panel made of flatsawn cherry, 12" wide, increasing in moisture
> content from 8% to 12%:
> D = 12" * 0.00248 * (12 - 8) = 0.12"
> In other words, this panel will increase in width by nearly 1/8".
>
> 2. A panel made of quartersawn white oak, 18" wide, decreasing in
> moisture content from 13% to 7%:
> D = 18" * 0.00180 * (7 - 13) = -0.194" (note the negative sign)
> In other words, this panel will *decrease* in width by about 3/16".
>
> Hope this helps.
Do you mostly dry fit the rail and stiles first (using clamps and the
likes) and then measure the panel (from in-groove to in-groove then
subtract the allowance)? Or you do the calculations and trust on that (get
all the numbers from whatever math used and cut the work without second
thought or measuring twice?)?
I am asking because all the samples I did was for one-panel assembly and
the Excel worksheet worked "perfectly" but when I tried the two-panel
assembly, something went off (could be me or the arithmetic).
Chuck
Correct me...
warm air (summer), the wood EXPANDS
cold air (winter), the wood SHRINKS
Also, I am still trying to understand this...
in a summer time, I am building something in the cool basement with the
dehumidifier running, should I still consider the wood is already in it's
full expansion?
(still in summer in cool basement) if the wood is in full expansion, I
should then make the raised panel tight, since it will only shrink when
the winter comes. Correct?
Chuck
> I am see the differences in between the depths of 3/8" and 7/16"
> router bits. Using (1/4") space balls, the 3/8" depth will only leave
> ~1/8" left for the panels to tuck in, while 7/16" will leave ~3/16"
> left.
>
> I have yet to study the following. I am wondering if the following
> affects (still talking about raised panels projects):
>
> 1) If the project was to be build in south (FL, TX, AZ, etc) and to
> stay there, would this (shrinkage) still matter?
>
> 2) If I was to build something in the summer (north, WI, IL, MN, OR,
> etc), I should expect the wood is in it's full stretched position?
>
> 3) As to #2, if I was building the project in the summer, but a cool
> basement (most would have dehumidifier running), what would the
> "barometer" be?
>
> 4) If I was building a project in the winter (north), the wood would
> be in it's most shrunken? The house (indoors) humidity doesn't count
> as the outside?
>
> Forgive me if this is none sense or too techincal. But, gotta ask
> away!
>
> Chuck
>
>> Change in width depends on the type of wood, the width of the panel,
>> and the amount of change in moisture content.
>>
>> It can be estimated using this formula:
>> D = W * k * (M2 - M1)
>> where
>> - D is the change in dimension
>> - W is the width of the panel
>> - k is the dimensional change coefficient, which is different for
>> each species and different for radial and tangential expansion
>> - M1 is the original moisture content in percent
>> - M2 is the new moisture content in percent
>>
>> Sample values of k:
>> Cherry: 0.00126 radial, 0.00248 tangential
>> Sugar maple: 0.00165, 0.00353
>> White oak: 0.00180, 0.00365
>> Walnut: 0.00190, 0.00308
>>
>> Formula and coefficients taken from "Wood Handbook: Wood as an
>> Engineering Material", chapter 12, available online at
>> http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch12.pdf
>>
>> For flatsawn lumber, use the tangential coefficient to figure the
>> change in width; for quartersawn lumber, use the radial coefficient.
>>
>> Examples:
>>
>> 1. A panel made of flatsawn cherry, 12" wide, increasing in moisture
>> content from 8% to 12%:
>> D = 12" * 0.00248 * (12 - 8) = 0.12"
>> In other words, this panel will increase in width by nearly 1/8".
>>
>> 2. A panel made of quartersawn white oak, 18" wide, decreasing in
>> moisture content from 13% to 7%:
>> D = 18" * 0.00180 * (7 - 13) = -0.194" (note the negative sign)
>> In other words, this panel will *decrease* in width by about 3/16".
>>
>> Hope this helps.
OK... so, when I am plan doing the work that day, I just turn off the
dehumidifier, open two little windows the day before and during the work
day. That should give enough time for the wood to drink?
I am finally finish with school and have summer off! Time to study this
topic. David, I will read that link you gave me SOON.
Chuck
> No. It could expand further if the final place for the piece has a
> higher humidity than your dehumidified basement.
"CNT" <[email protected]> wrote in message
news:[email protected]...
> I am see the differences in between the depths of 3/8" and 7/16" router
> bits. Using (1/4") space balls, the 3/8" depth will only leave ~1/8" left
> for the panels to tuck in, while 7/16" will leave ~3/16" left.
>
> I have yet to study the following. I am wondering if the following affects
> (still talking about raised panels projects):
>
> 1) If the project was to be build in south (FL, TX, AZ, etc) and to stay
> there, would this (shrinkage) still matter?
Yep. Air conditioning can dry things pretty well.
>
> 2) If I was to build something in the summer (north, WI, IL, MN, OR, etc),
> I should expect the wood is in it's full stretched position?
>
Building in the basement, perhaps. Upstairs, no
> 3) As to #2, if I was building the project in the summer, but a cool
> basement (most would have dehumidifier running), what would the
> "barometer" be?
Now there's a question with no answer.
>
> 4) If I was building a project in the winter (north), the wood would be in
> it's most shrunken? The house (indoors) humidity doesn't count as the
> outside?
>
Warmer air is capable of holding more water - absolute humidity - than cold.
The cold outside air, warmed, lowers the realtive humidity in the heated
area.
> Forgive me if this is none sense or too techincal. But, gotta ask away!
>
> Chuck
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm
In article <[email protected]>, CNT <[email protected]> wrote:
>What is the length and width for Panel Expansion Allowance? I like to use
>space balls.
Change in length is so close to zero that you don't need to make any allowance
for it whatsoever.
Change in width depends on the type of wood, the width of the panel, and the
amount of change in moisture content.
It can be estimated using this formula:
D = W * k * (M2 - M1)
where
- D is the change in dimension
- W is the width of the panel
- k is the dimensional change coefficient, which is different for each species
and different for radial and tangential expansion
- M1 is the original moisture content in percent
- M2 is the new moisture content in percent
Sample values of k:
Cherry: 0.00126 radial, 0.00248 tangential
Sugar maple: 0.00165, 0.00353
White oak: 0.00180, 0.00365
Walnut: 0.00190, 0.00308
Formula and coefficients taken from "Wood Handbook: Wood as an Engineering
Material", chapter 12, available online at
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch12.pdf
For flatsawn lumber, use the tangential coefficient to figure the change in
width; for quartersawn lumber, use the radial coefficient.
Examples:
1. A panel made of flatsawn cherry, 12" wide, increasing in moisture content
from 8% to 12%:
D = 12" * 0.00248 * (12 - 8) = 0.12"
In other words, this panel will increase in width by nearly 1/8".
2. A panel made of quartersawn white oak, 18" wide, decreasing in moisture
content from 13% to 7%:
D = 18" * 0.00180 * (7 - 13) = -0.194" (note the negative sign)
In other words, this panel will *decrease* in width by about 3/16".
Hope this helps.
--
Regards,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
In article <[email protected]>, "Leon" <[email protected]> wrote:
>If your panels are mounting "tilted" your panels may be fitting too tightly
>in the slots and not floating properly.
>
Or he may be using only one SpaceBall per side - should be two.
--
Regards,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
On Wed, 11 May 2005 19:27:55 -0000, CNT <[email protected]> wrote:
>What is the length and width for Panel Expansion Allowance? I like to use
>space balls.
>
>One say:
>1/8" for width
>1/16" for height
>
>Another say:
>3/8" for width
>1/4" for height
>
>How to figure the allowance if it's preferences? When I did samples (with
>space balls), I mark the panels with pencil, then take it apart and see
>it's tilted.
>
>Chuck
I do the calculations referenced in another posting in this thread,
but don't use spaceballs. I use brads and pin the panel with wire
brads top and bottom in the center from behind. So far, so good.
"CNT" <[email protected]> wrote in message
news:[email protected]...
> So, lets say you have 7/16" bits (which is almost 1/2"), you cut another
> 1/4" alone off in D ( D from my picture in previous post)?
>
> Or you just adjust the panel size in that only ~1/4" tucks in each sides
> (with space balls inserted)?
>
> I think you're right, I may have attempt to assemble things too tight.
Width and length of the panel are not too critical as long as you are close.
The tightness I am talking about is the thickness of the panel going into
the slot.
Also if the panel goes into the slot too far and the raised profile begins
to go into the slot this can be a problem also. Basically you only want the
"flat thin outer edge" of the panel to go into the slot. If the raised part
of the panel profile is starting to go into the slot the panel is too wide
or long.
I can draw a you a picture on a PDF file if you like.
In article <[email protected]>, CNT <[email protected]> wrote:
>OK... so, when I am plan doing the work that day, I just turn off the
>dehumidifier, open two little windows the day before and during the work
>day. That should give enough time for the wood to drink?
NO. The last thing you want is for the wood to be absorbing and releasing
humidity - thus changing size and shape - while you're still working on it.
Keep the dehumidifier running all the time. Or none of the time. Ideally, you
want to work the work under approximately the same humidity conditions as it
will be exposed to as a finished piece. In a centrally heated and air
conditioned house, with a basement workshop, this means running the
dehumidifier.
--
Regards,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
Think humidity instead of temperature.
CNT wrote:
> Correct me...
> warm air (summer), the wood EXPANDS
> cold air (winter), the wood SHRINKS
>
> Also, I am still trying to understand this...
> in a summer time, I am building something in the cool basement with the
> dehumidifier running, should I still consider the wood is already in it's
> full expansion?
>
> (still in summer in cool basement) if the wood is in full expansion, I
> should then make the raised panel tight, since it will only shrink when
> the winter comes. Correct?
>
> Chuck
>
>
You might consider staining door panels BEFORE assembling the door so
that future shrinkage, if it occurs, will not result in a light band of
unfinished wood, spoiling the appearance.
Dave
CNT wrote:
> OK... so, when I am plan doing the work that day, I just turn off the
> dehumidifier, open two little windows the day before and during the work
> day. That should give enough time for the wood to drink?
>
> I am finally finish with school and have summer off! Time to study this
> topic. David, I will read that link you gave me SOON.
>
> Chuck
>
>
>>No. It could expand further if the final place for the piece has a
>>higher humidity than your dehumidified basement.
In article <[email protected]>, CNT <[email protected]> wrote:
>Correct me...
>warm air (summer), the wood EXPANDS
>cold air (winter), the wood SHRINKS
Incorrect. *Humid* air, the wood expands; *dry* air, the wood shrinks. If your
house has central heat and central A/C, and in the spring and fall you run
*neither* but leave your windows open, the greatest expansion will occur
during the spring, not the summer.
>
>Also, I am still trying to understand this...
>in a summer time, I am building something in the cool basement with the
>dehumidifier running, should I still consider the wood is already in it's
>full expansion?
I shouldn't think so, not with a dehumidifier.
--
Regards,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?
The slots that my panels fit into are about 1/2" deep. The space balls are
just over 1/4" in diameter. I make the panels to be 1/2" total longer and
1/2" total wider than the inside of dry fit rails and stiles.
The space balls compress slightly and hold the panel evenly suspended.
Basically 1/16" to 1/8" larger than the available space between the balls.
If your panels are mounting "tilted" your panels may be fitting too tightly
in the slots and not floating properly.
The trouble with many raised panel cutters with back cutters is that the
back cutter may not cut enough or cut too little for the panel to float
properly with in the door frame.
"CNT" <[email protected]> wrote in message
news:[email protected]...
> What is the length and width for Panel Expansion Allowance? I like to use
> space balls.
>
> One say:
> 1/8" for width
> 1/16" for height
>
> Another say:
> 3/8" for width
> 1/4" for height
>
> How to figure the allowance if it's preferences? When I did samples (with
> space balls), I mark the panels with pencil, then take it apart and see
> it's tilted.
>
> Chuck
Why not forget the space balls and use Dugs figures for panel expansion with
a brad at the center of the panel both top and bottom
"CNT" <[email protected]> wrote in message
news:[email protected]...
> I am see the differences in between the depths of 3/8" and 7/16" router
> bits. Using (1/4") space balls, the 3/8" depth will only leave ~1/8" left
> for the panels to tuck in, while 7/16" will leave ~3/16" left.
>
> I have yet to study the following. I am wondering if the following affects
> (still talking about raised panels projects):
>
> 1) If the project was to be build in south (FL, TX, AZ, etc) and to stay
> there, would this (shrinkage) still matter?
>
> 2) If I was to build something in the summer (north, WI, IL, MN, OR, etc),
> I should expect the wood is in it's full stretched position?
>
> 3) As to #2, if I was building the project in the summer, but a cool
> basement (most would have dehumidifier running), what would the
> "barometer" be?
>
> 4) If I was building a project in the winter (north), the wood would be in
> it's most shrunken? The house (indoors) humidity doesn't count as the
> outside?
>
> Forgive me if this is none sense or too techincal. But, gotta ask away!
>
> Chuck
>
> > Change in width depends on the type of wood, the width of the panel,
> > and the amount of change in moisture content.
> >
> > It can be estimated using this formula:
> > D = W * k * (M2 - M1)
> > where
> > - D is the change in dimension
> > - W is the width of the panel
> > - k is the dimensional change coefficient, which is different for each
> > species and different for radial and tangential expansion
> > - M1 is the original moisture content in percent
> > - M2 is the new moisture content in percent
> >
> > Sample values of k:
> > Cherry: 0.00126 radial, 0.00248 tangential
> > Sugar maple: 0.00165, 0.00353
> > White oak: 0.00180, 0.00365
> > Walnut: 0.00190, 0.00308
> >
> > Formula and coefficients taken from "Wood Handbook: Wood as an
> > Engineering Material", chapter 12, available online at
> > http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/ch12.pdf
> >
> > For flatsawn lumber, use the tangential coefficient to figure the
> > change in width; for quartersawn lumber, use the radial coefficient.
> >
> > Examples:
> >
> > 1. A panel made of flatsawn cherry, 12" wide, increasing in moisture
> > content from 8% to 12%:
> > D = 12" * 0.00248 * (12 - 8) = 0.12"
> > In other words, this panel will increase in width by nearly 1/8".
> >
> > 2. A panel made of quartersawn white oak, 18" wide, decreasing in
> > moisture content from 13% to 7%:
> > D = 18" * 0.00180 * (7 - 13) = -0.194" (note the negative sign)
> > In other words, this panel will *decrease* in width by about 3/16".
> >
> > Hope this helps.
CNT wrote:
> Correct me...
> warm air (summer), the wood EXPANDS
> cold air (winter), the wood SHRINKS
Wood expands when it absorbs moisture.
Wood shrinks when it dries.
Humidity causes the change. Temperature has little to do with the change
other than cold air usually contains less moisture.
>
> Also, I am still trying to understand this...
> in a summer time, I am building something in the cool basement with the
> dehumidifier running, should I still consider the wood is already in it's
> full expansion?
No. It could expand further if the final place for the piece has a
higher humidity than your dehumidified basement.
>
> (still in summer in cool basement) if the wood is in full expansion, I
> should then make the raised panel tight, since it will only shrink when
> the winter comes. Correct?
See above.
--
Jack Novak
Buffalo, NY - USA
[email protected]
(Remove -SPAM- to send email)
In article <[email protected]>, CNT <[email protected]> wrote:
>For nails, use 1/8" for width.
Oh, really? Suppose you have a panel of flatsawn white oak, 12" wide. An
increase in moisture content from 8% to 12% (easily the result of the
difference between winter and summer humidity) will cause that panel to expand
in width by almost 3/16". If you allowed only 1/8" for expansion... you have a
problem.
>With space balls, use 1/2" for width (and height).
You can't use any arbitrary figure, without taking into account the width of
the panel, the species of wood, and whether it's flat- or quarter-sawn.
--
Regards,
Doug Miller (alphageek at milmac dot com)
Nobody ever left footprints in the sands of time by sitting on his butt.
And who wants to leave buttprints in the sands of time?