I am just getting into clamping up boards for table tops, etc..
Aren't you supposed to make the jointed edges straight, so the you don't
NEED much clamping pressure?
I have a limited variety of bar and pipe clamps. Some are more rigid than
others. Sometimes I have to use cauls to keep things flat because some of
my clamps do bow somewhat. I assumed that I just have to work harder to get
everything straight and to do the gluing and clamping immediately after
final jointer work so things don't have a change to deform overnight.
Am I just putting too much effort into making straight boards in the first
place?
Am I wasting too much wood trying to get things straight? (I only have a
jointer with a 4 foot bed.)
If I spend the money on heavy duty clamps, then can I get away with wavy
boards, or is there a downside to using huge clamping pressures later on?
Pete Stanaitis
---------------
When the width of a panel is such that its apt to bow or flex when
clamped, apply your clamps alternately on the top and bottom sides of
the panel. Their pressure, alternately on each side of the panel,
will help lessen the bowing, more so, one way or the other.
When there is a bit of bowing, I have sometimes use C-clamps, with
3/4" ply blocks each side of the panel, acting as spot-cauls at those
immediate bowed areas, to help lessen the bowing at that spot.
If you have the plywood (and the storage area for them), making a good
set of "I-beams", similarly as those units Swingman has, would
probably be great for keeping panels from bowing, while clamping.
Below includes Karl's comment from "Makeshift Vise" thread:
> Morning Fellows I have a bit of a problem I don't have a proper work bench
> , not enough room in garage, I use a couple of pieces of 3/4" ply on top of
> each other over sawhorses. I have a number of 3/4" x 3" oak slats from
> outdoor benches to sand . How do I hold them securely to be able to face
> sand them with out vice jaws getting in the way.
Got some scrap plywood?
Take an hour and make some of these:
https://picasaweb.google.com/111355467778981859077/EWoodShopJigsFixtu...
The can be be clamped to just about any surface, and "stuff" can be
clamped to them ... innumerable uses such as this:
https://picasaweb.google.com/111355467778981859077/EWoodShopJustStuff...
and this:
https://picasaweb.google.com/111355467778981859077/EWoodShopEuropeanS...
Handy, up to the limits of your imagination, guaranteed.
--
Sonny
I would guess that depends on where you live.
If you live in Nevada not an issue (arid).
If you live in the North East... ISSUE.
The humidity here in the summer and the cold dry air in the winter makes
it a bigger deal.
If you live somewhere that its always humid no big deal either.
On 6/17/2012 12:41 PM, -MIKE- wrote:
> On 6/17/12 11:03 AM, tiredofspam wrote:
>> First of all, your boards should not be straight to join them.
>> They should bow in a little toward the center. So that the ends touch
>> first. The reason is that during seasonal changes shrinkage happens at
>> the ends first, and if perfectly jointed the boards will split at the
>> ends.
>
> Acceptance or practice of that theory is hardly ubiquitous in the
> woodworking community.
>
>
"-MIKE-" wrote in message news:[email protected]...
On 6/17/12 11:03 AM, tiredofspam wrote:
> First of all, your boards should not be straight to join them.
> They should bow in a little toward the center. So that the ends touch
> first. The reason is that during seasonal changes shrinkage happens at
> the ends first, and if perfectly jointed the boards will split at the
> ends.
Acceptance or practice of that theory is hardly ubiquitous in the
woodworking community.
======================================================T
Quite true. I have seen some people do it that way but the vast majority get
them strait as possible before glue up. My sister has a table that my father
built when I was 1 year old in Germany. We had it with us in Ethiopia,
Turkey and Japan. It has also been from coast to coast in the U.S. It now
resides in Texas. Beside the dings it has picked up over the years, it is in
perfect shape. Nothing loose and no splits or cracks. I have a coffee table
and end table that he built in Japan in the mid 70s. They went from there
(humid) to eastern Washington state (very dry) to western Washington
(humid). They too are perfectly sound. My father believed in strait and
tight fitting joints. So do I.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
First of all, your boards should not be straight to join them.
They should bow in a little toward the center. So that the ends touch
first. The reason is that during seasonal changes shrinkage happens at
the ends first, and if perfectly jointed the boards will split at the ends.
After jointing on the joiner, I hand joint the bow in..
You always need to apply proper pressure to glue up boards. Not light
pressure. Heavy pressure. I use light pressure to align... Then heavy
to clamp.
On 6/16/2012 12:03 PM, Pete S wrote:
> I am just getting into clamping up boards for table tops, etc..
> Aren't you supposed to make the jointed edges straight, so the you don't
> NEED much clamping pressure?
>
> I have a limited variety of bar and pipe clamps. Some are more rigid
> than others. Sometimes I have to use cauls to keep things flat because
> some of my clamps do bow somewhat. I assumed that I just have to work
> harder to get everything straight and to do the gluing and clamping
> immediately after final jointer work so things don't have a change to
> deform overnight.
>
> Am I just putting too much effort into making straight boards in the
> first place?
> Am I wasting too much wood trying to get things straight? (I only have a
> jointer with a 4 foot bed.)
> If I spend the money on heavy duty clamps, then can I get away with wavy
> boards, or is there a downside to using huge clamping pressures later on?
>
> Pete Stanaitis
> ---------------
"tiredofspam" wrote in message
news:[email protected]...
I would guess that depends on where you live.
If you live in Nevada not an issue (arid).
If you live in the North East... ISSUE.
The humidity here in the summer and the cold dry air in the winter makes
it a bigger deal.
If you live somewhere that its always humid no big deal either.
===========================================================================
See my post on the subject.
On 6/17/2012 12:41 PM, -MIKE- wrote:
> On 6/17/12 11:03 AM, tiredofspam wrote:
>> First of all, your boards should not be straight to join them.
>> They should bow in a little toward the center. So that the ends touch
>> first. The reason is that during seasonal changes shrinkage happens at
>> the ends first, and if perfectly jointed the boards will split at the
>> ends.
>
> Acceptance or practice of that theory is hardly ubiquitous in the
> woodworking community.
>
>
On 6/16/12 11:03 AM, Pete S wrote:
> I am just getting into clamping up boards for table tops, etc..
> Aren't you supposed to make the jointed edges straight, so the you don't
> NEED much clamping pressure?
>
> I have a limited variety of bar and pipe clamps. Some are more rigid
> than others. Sometimes I have to use cauls to keep things flat because
> some of my clamps do bow somewhat. I assumed that I just have to work
> harder to get everything straight and to do the gluing and clamping
> immediately after final jointer work so things don't have a change to
> deform overnight.
>
> Am I just putting too much effort into making straight boards in the
> first place?
> Am I wasting too much wood trying to get things straight? (I only have a
> jointer with a 4 foot bed.)
> If I spend the money on heavy duty clamps, then can I get away with wavy
> boards, or is there a downside to using huge clamping pressures later on?
>
> Pete Stanaitis
> ---------------
Just my opinion on a few of your thoughts....
I don't think a woodworker worth his salt is buying heavy clamps with
the purpose of joining wavy edged boards. Most do their very best to
produce a straight board in the first place. The straighter the boards,
less clamping pressure you need, obviously. I stopped using the jointer
for edge panels once I got a decent table saw (& fence) and glue-line
blade. A saw with enough power, properly set up to be perfectly square
and parallel, with a good, sharp, rip blade will give results that will
allow you to skip the jointer.
Don't looks at cauls as a "have to" tool. Instead, look at them as a
"get to." Like any other jig or tool, they make the job easier and
improve the results.
I also have a limited supply of clamps. Last time I glued up some wide
panels, I did something that made it easier with fewer clamps. I only
glued panels wide enough to fit through my planer. I then ran the
narrower glued panels through the planer and glued them together to
their final, or near final width. I used a card scraper on the
remaining glue joint to feather the edge perfect where it wasn't. I
found this to be a very efficient and less stressful way to manage the
process of making wide panels without dozens of large, heavy cabinet
clamps. Also, I found it easier to cut the panels to final dimensions
after gluing them up a little larger. Under some circumstances, this
also makes things less stressful and more efficient.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 6/16/2012 11:03 AM, Pete S wrote:
> I am just getting into clamping up boards for table tops, etc..
> Aren't you supposed to make the jointed edges straight, so the you don't
> NEED much clamping pressure?
...
Test data indicates that glued joint strength increases w/ higher
clamping pressures up to very high values (US Forest Products Lab and
others; DAGS if you're really into the details. I've posted these links
in the past in this newsgroup so the google archives are another place
to look; again only if you really care; in general I'd say it's not of
significance to worry about).
The thing about the clamping force is that the actual pressure applied
along the length of the board between clamps drops off w/ distance so to
get a significant force along the entire length requires some way to
either distribute that force more uniformly, increase the applied force
and/or use more clamps.
And, of course, the quality of a joint is definitely dependent on the
preparation--a pair of boards that aren't well fitting may be brought
together by force and the glue will hold them together when dry and the
clamps removed but that residual strain will still be there and be a
source of movement and/or even joint failure w/ time.
So, the answer is that yes, you should try to make joints fit and yes,
best results are still obtained when clamping pressures are fairly high.
But, you generally don't need to bend a stout clamp, either... :)
--
On 6/16/12 12:20 PM, dpb wrote:
> On 6/16/2012 11:03 AM, Pete S wrote:
>> I am just getting into clamping up boards for table tops, etc..
>> Aren't you supposed to make the jointed edges straight, so the you don't
>> NEED much clamping pressure?
> ...
>
> Test data indicates that glued joint strength increases w/ higher
> clamping pressures up to very high values (US Forest Products Lab and
> others; DAGS if you're really into the details. I've posted these links
> in the past in this newsgroup so the google archives are another place
> to look; again only if you really care; in general I'd say it's not of
> significance to worry about).
>
> The thing about the clamping force is that the actual pressure applied
> along the length of the board between clamps drops off w/ distance so to
> get a significant force along the entire length requires some way to
> either distribute that force more uniformly, increase the applied force
> and/or use more clamps.
>
> And, of course, the quality of a joint is definitely dependent on the
> preparation--a pair of boards that aren't well fitting may be brought
> together by force and the glue will hold them together when dry and the
> clamps removed but that residual strain will still be there and be a
> source of movement and/or even joint failure w/ time.
>
> So, the answer is that yes, you should try to make joints fit and yes,
> best results are still obtained when clamping pressures are fairly high.
>
> But, you generally don't need to bend a stout clamp, either... :)
>
> --
I've seen and read these reports, but what we really have to ask
ourselves is, "is it really applicable to the project?"
For your typical woodworker's panel project, a table or a cabinet door,
how strong does the joint really need to be? We already know that most
panels will split in the middle of a board instead of the glue joint.
We already know that most edged glue joints aren't being used for any
kind of real load bearing.... so again, why bother with the ridiculously
high clamping pressures?
It's akin to the arguments we get into about accuracy. Do we need
accuracy in woodworking that gets down to the width of an atom? No, we
need accuracy somewhere around the amount the measured distance will
increase or decrease to to expansion and contraction of the wood. We're
not building o-rings for the space shuttle. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 6/16/2012 1:30 PM, -MIKE- wrote:
> On 6/16/12 12:20 PM, dpb wrote:
...
>> So, the answer is that yes, you should try to make joints fit and yes,
>> best results are still obtained when clamping pressures are fairly high.
>>
>> But, you generally don't need to bend a stout clamp, either... :)
...
> I've seen and read these reports, but what we really have to ask
> ourselves is, "is it really applicable to the project?"
> For your typical woodworker's panel project, a table or a cabinet door,
> how strong does the joint really need to be? We already know that most
> panels will split in the middle of a board instead of the glue joint. We
> already know that most edged glue joints aren't being used for any kind
> of real load bearing.... so again, why bother with the ridiculously high
> clamping pressures?
>
> It's akin to the arguments we get into about accuracy. Do we need
> accuracy in woodworking that gets down to the width of an atom? No, we
> need accuracy somewhere around the amount the measured distance will
> increase or decrease to to expansion and contraction of the wood. We're
> not building o-rings for the space shuttle. :-)
Well, if I didn't put enough caveats in for you the last sentence above
should have done.
But, my take is if you're bothering to do a glueup for anything that's
not just throw-away craftwork, why not make it be "the best it can be"
or why bother? I'm convinced from the difference between my early and
later work's longevity (and I'm enough of an ol' phar... by now that
early stuff is past 40 which is starting to get enough to see what
did/didn't work) that glue joints last longer w/ higher pressures and
better fitting than without as well.
When I first began, all I had was some pretty light Big Lots-type bar
clamps and while the old Craftsman jointer was set up well, some of
those panels have developed problems w/ age whereas later don't show
signs as of yet...
So, my general advice to OP is my stand on the subject...I'll agree that
the extremely high pressures studied under some of the conditions by US
FPL for commercial manufacturers are beyond the need of individuals, the
general trends shown there are worthy of noting.
--
On 6/16/12 3:13 PM, dpb wrote:
> On 6/16/2012 1:30 PM, -MIKE- wrote:
>> On 6/16/12 12:20 PM, dpb wrote:
> ...
>
>>> So, the answer is that yes, you should try to make joints fit and yes,
>>> best results are still obtained when clamping pressures are fairly high.
>>>
>>> But, you generally don't need to bend a stout clamp, either... :)
> ...
>
>> I've seen and read these reports, but what we really have to ask
>> ourselves is, "is it really applicable to the project?"
>> For your typical woodworker's panel project, a table or a cabinet door,
>> how strong does the joint really need to be? We already know that most
>> panels will split in the middle of a board instead of the glue joint. We
>> already know that most edged glue joints aren't being used for any kind
>> of real load bearing.... so again, why bother with the ridiculously high
>> clamping pressures?
>>
>> It's akin to the arguments we get into about accuracy. Do we need
>> accuracy in woodworking that gets down to the width of an atom? No, we
>> need accuracy somewhere around the amount the measured distance will
>> increase or decrease to to expansion and contraction of the wood. We're
>> not building o-rings for the space shuttle. :-)
>
> Well, if I didn't put enough caveats in for you the last sentence above
> should have done.
>
The subject comes up again and again and for a beginner reading this
thread, it's worth presenting both sides, again.
> But, my take is if you're bothering to do a glueup for anything that's
> not just throw-away craftwork, why not make it be "the best it can be"
> or why bother?
Because you reach a point (I would argue, quite soon) of diminishing
returns. Using your argument, we should all be using a micrometer for
all our measurements. We should be be sanding down to 1500grit on
everything. Why not? It's smoother.
> I'm convinced from the difference between my early and
> later work's longevity (and I'm enough of an ol' phar... by now that
> early stuff is past 40 which is starting to get enough to see what
> did/didn't work) that glue joints last longer w/ higher pressures and
> better fitting than without as well.
>
I'm not saying glue joints don't last longer with higher pressures. I'm
saying, you reach a point where it doesn't matter at a much lower
pressure than you'd think.
> When I first began, all I had was some pretty light Big Lots-type bar
> clamps and while the old Craftsman jointer was set up well, some of
> those panels have developed problems w/ age whereas later don't show
> signs as of yet...
Maybe it's not the gluing pressure you used. Maybe it's all the other
factors that come into being when you're less experienced.
> So, my general advice to OP is my stand on the subject...I'll agree that
> the extremely high pressures studied under some of the conditions by US
> FPL for commercial manufacturers are beyond the need of individuals,
My only point.
> the general trends shown there are worthy of noting.
>
... and only noting. :-)
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 6/17/12 11:03 AM, tiredofspam wrote:
> First of all, your boards should not be straight to join them.
> They should bow in a little toward the center. So that the ends touch
> first. The reason is that during seasonal changes shrinkage happens at
> the ends first, and if perfectly jointed the boards will split at the ends.
Acceptance or practice of that theory is hardly ubiquitous in the
woodworking community.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 6/17/12 2:25 PM, tiredofspam wrote:
> I would guess that depends on where you live.
>
> If you live in Nevada not an issue (arid).
> If you live in the North East... ISSUE.
>
> The humidity here in the summer and the cold dry air in the winter makes
> it a bigger deal.
>
> If you live somewhere that its always humid no big deal either.
>
That's the the issue I'm talking about.
No one argues RH changes cause wood to expand and contract.
What is not universally excepted in woodworking is the practice of
joining bowed instead of straight boards to keep them from cracking at
the ends.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
On 6/17/12 3:33 PM, tiredofspam wrote:
> That's what's beautiful about this hobby and country.
> You can believe or do what you want.
>
> To each his own.. I'll still prepare mine as I do. It works for me, and
> has never split. I have refinished things that have split (none that I
> made)
>
> A student's desk.
> A cutting board. (really gets wet then dry quickly)
> A table.
>
>
> I chose to believe that my repairs by cutting down the split, then
> jointing and springing helped. They have not failed since.
>
> Sorry if I misspelled or are unclear, I have one eye patched right now..
> I think I cut my cornea again... damn..
>
I would credit the glue and not the cut.
--
-MIKE-
"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
http://mikedrums.com
[email protected]
---remove "DOT" ^^^^ to reply
In article <[email protected]>,
-MIKE- <[email protected]> wrote:
>On 6/17/12 11:03 AM, tiredofspam wrote:
>> First of all, your boards should not be straight to join them.
>> They should bow in a little toward the center. So that the ends touch
>> first. The reason is that during seasonal changes shrinkage happens at
>> the ends first, and if perfectly jointed the boards will split at the ends.
>
>Acceptance or practice of that theory is hardly ubiquitous in the
>woodworking community.
>
>
Couldn't have said that better myself! :)
(Though I usually do aim for a very slightly sprung joint)
--
Better to be stuck up in a tree than tied to one.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org
In article <[email protected]>,
-MIKE- <[email protected]> wrote:
>On 6/17/12 2:25 PM, tiredofspam wrote:
>> I would guess that depends on where you live.
>>
>> If you live in Nevada not an issue (arid).
>> If you live in the North East... ISSUE.
>>
>> The humidity here in the summer and the cold dry air in the winter makes
>> it a bigger deal.
>>
>> If you live somewhere that its always humid no big deal either.
>>
>
>That's the the issue I'm talking about.
>No one argues RH changes cause wood to expand and contract.
>What is not universally excepted in woodworking is the practice of
>joining bowed instead of straight boards to keep them from cracking at
>the ends.
>
>
Besides, a panel that opens up in the middle but the with the ends
staying intact is not unheard of (should that be unseen of?)
--
Better to be stuck up in a tree than tied to one.
Larry Wasserman - Baltimore Maryland - lwasserm(a)sdf. lonestar.org
That's what's beautiful about this hobby and country.
You can believe or do what you want.
To each his own.. I'll still prepare mine as I do. It works for me, and
has never split. I have refinished things that have split (none that I made)
A student's desk.
A cutting board. (really gets wet then dry quickly)
A table.
I chose to believe that my repairs by cutting down the split, then
jointing and springing helped. They have not failed since.
Sorry if I misspelled or are unclear, I have one eye patched right now..
I think I cut my cornea again... damn..
On 6/17/2012 4:05 PM, CW wrote:
>
>
> "-MIKE-" wrote in message news:[email protected]...
>
> On 6/17/12 11:03 AM, tiredofspam wrote:
>> First of all, your boards should not be straight to join them.
>> They should bow in a little toward the center. So that the ends touch
>> first. The reason is that during seasonal changes shrinkage happens at
>> the ends first, and if perfectly jointed the boards will split at the
>> ends.
>
> Acceptance or practice of that theory is hardly ubiquitous in the
> woodworking community.
> ======================================================T
> Quite true. I have seen some people do it that way but the vast majority
> get them strait as possible before glue up. My sister has a table that
> my father built when I was 1 year old in Germany. We had it with us in
> Ethiopia, Turkey and Japan. It has also been from coast to coast in the
> U.S. It now resides in Texas. Beside the dings it has picked up over the
> years, it is in perfect shape. Nothing loose and no splits or cracks. I
> have a coffee table and end table that he built in Japan in the mid 70s.
> They went from there (humid) to eastern Washington state (very dry) to
> western Washington (humid). They too are perfectly sound. My father
> believed in strait and tight fitting joints. So do I.
>
>