for people who do spring joints at times

[Warren Lake]

is there a formula for the gap you make? I did .013 on boards that are a final of 26" long. It might be a bit heavy. There is likely a point where there is a too much and be certain considerations type of wood, board width etc but maybe not. Never came up with the old guy but know had I asked there would have been a good answer or answers, there always was.

I know a few of you here do them any thoughts gap related to length?

While not what I want to ask consider a table top with 8 boards 6 inches wide. If done all with spring joints then your table top will be sunk in in width in the middle some amount. Easy enough to calculate when you know your gap.


thanks,



w

[Mel Fulks]

Warren, I think "just something". That is wayyy ahead of even a small opening at ends!! Especially with modern kiln
dried wood acclimated in a shop with temperature that is OK with glue instructions. Since more wood is taken off on front
end than the back end; it's best to do one edge then flip board end over end to make all parallel . If it is stain grade work.
And be sure to joint one board face "in" (to fence ) and next "out". Then you don't have to worry about the fence
moving ....like they all do. Just let it sag to stability !

[Mel Fulks]

You definately need to have all your boards jointed ,or straight-lined before doing the spring jointing . Got to have a straight "track". Finished glue up needs to be jointed with standard set up and ripped to have uniform width. Or it
would not be parallel

[Joe Calhoon]

Warren, I do spring joints on larger glue ups. I believe it helps end splitting. Especially in a dry climate. Never measured the gap but it’s pretty slight. Probably close to what you say. I usually straight line and rip to consistent width before putting the spring joint on. Small panels less than say 2’ in length the spring joint is hardly noticeable.
and I don’t worry if everything comes out parallel as panels get sized after glue up.

[Warren Lake]

thanks

yeah boards were jointed and ripped other side first. Mel so you have to do an edge twice from one end then turn it around go the other way? thats new to me but had never asked one of the old guys. I do the face in out thing but have also made sure the jointer fence is square first each time. Those are very light fences on the scm, because its a combo they cut down on the weight knowing its on and off all the time. Want to try the larger jointer but still havent had time to focus on it. I had added baltic birch onto the jointer fence to make it a bit taller and longer and that was an improvement. This smaller thing I just trued it up to straight on the edge sander, had to be edge sanded first and of course both ends sanded first before the middle. Joe I think I went too heavy on my gap for the 26" length but im just testing some stuff out and working things out on it

Ill test the turn around thing later today. thanks to both.

[Mark Bolton]

thanks

yeah boards were jointed and ripped other side first. Mel so you have to do an edge twice from one end then turn it around go the other way? thats new to me but had never asked one of the old guys. I do the face in out thing but have also made sure the jointer fence is square first each time. Those are very light fences on the scm, because its a combo they cut down on the weight knowing its on and off all the time. Want to try the larger jointer but still havent had time to focus on it. I had added baltic birch onto the jointer fence to make it a bit taller and longer and that was an improvement. This smaller thing I just trued it up to straight on the edge sander, had to be edge sanded first and of course both ends sanded first before the middle. Joe I think I went too heavy on my gap for the 26" length but im just testing some stuff out and working things out on it

Ill test the turn around thing later today. thanks to both.


We spring most everything we can but I cant say Ive ever measured. I would guess on some we are heavier than yours. .013" is pretty tight but as Mel says, anything is better than the alternative (open at the ends and trying to clamp it out).

[Mel Fulks]

I just meant you don't want to try putting spring joint on boards that don't already have a straight edge. And for stain
grade stuff you don't want non parallel boards ,as no matter how carefully the grain match the eye will be distracted by
non parallel . So you start with boards sawn parallel. Joint one edge ,then turn it end over end before jointing other edge.
Remember on a spring joint more wood is removed from the leading end than the trailing end.

[Richard Coers]

I usually just look for light in the middle when I do a glue joint, but .013" would be way too much on an 8-10" wide board

[Derek Cohen]

is there a formula for the gap you make? I did .013 on boards that are a final of 26" long. It might be a bit heavy. There is likely a point where there is a too much and be certain considerations type of wood, board width etc but maybe not. Never came up with the old guy but know had I asked there would have been a good answer or answers, there always was.

I know a few of you here do them any thoughts gap related to length?

While not what I want to ask consider a table top with 8 boards 6 inches wide. If done all with spring joints then your table top will be sunk in in width in the middle some amount. Easy enough to calculate when you know your gap.


thanks,



w

Warren, it very much depends on the wood. How much springiness is there in the board. One rule of thumb is that one can close up the gap by pushing the boards together without a clamp.

Regards from Perth

Derek

[Warren Lake]

Mel got what you meant and i had jointed and ripped to width so fine and it was good to mention just in case i hadnt jointed and width ripped first, appreciate you mentioned it as you arent seeing how I work but looking out for me. Richard makes sense but would depend on the length an 8 foot table top diff than 26" in this case. .013 is 3 - 4 hairs approx. Derek pushing together by hand hard to see that on a wider board. makes sense that board type width thickness etc all affect it. Ill agree that I did .013 on 26" and that is too much but im just doing a prototype and thinking and working out the thoughts. Mark thanks for mentioning you do it as well.

All good info, thanks,

[Andrew Hughes]

I also consider the width and thickness time of year rain or sun. I’ve found on 8/4 boards that I’ve milled down even at 6/4 I really don’t have enough clamps to squeeze out all the glue in a 8 to 10 inch wide board.
So I joint as accurate as possible I look for snipe on the ends. If I put a clamp on the ends and the opposite side opens up I know there more work to do.

[Warren Lake]

Honed my knives, checked how they are sitting above the head, lowered outfeed to snipe, raised outfeed to perfect, then past .0005 - .0015 for hollow. Thats good on the pressure and squeeze what kind of gap and how long are the boards?

[Don Stephan]

Haven't made one in a couple years but my rememberence is using a long plane set to take a thin shaving on say a 60" long edge, make a pass on just the middle 15" or so, then a pass on the middle 30" or so, then a pass on the middle 45" or so, then one fuill length pass. Stop each pass by lifting the end of the plane.

[Tom Bussey]

I don't do spring joints. The glue these days is stronger that the wood so if over done it puts stress in the wood and the board will split in the middle instead of the joint I have seen enough older tables with split pieces in the middle. And since the spring has to be put in by hand there is a possibility of getting the joint out of square. So why put in the extra work so that it might split down the road. All it does is allow a person to use fewer or one clamp. Why not get the mating boards right and use a few more clamps. It is a good reason as any to buy a couple more clamps.

[Warren Lake]

your barking up the wrong tree. Anyone who had to do that cause they didnt have enough clamps deserves what they get. They have created and built in a problem at that point.

The spring does not have to be put in by hand its achieved by raising the outfeed table on the jointer. Its one thing if boards are in a solid piece of furniture as sides top or bottom that are glued together, another if they are boards on a table top not joined to anything else at the ends as they are. Never once seen the results you said but did once see table top open at the ends and this is why this extra attention is paid.

[Tom Bussey]

Yes I know spring joints can be put it on a jointer. But why got the extra work. The splits in the boards I am referring to is when tops are glued a crossed the width not length. And I get asked to repair a lot of these splits in the middle of the board, not the glue joint. So we are back to the original question why go to the trouble of doing it it it doesn't add anything to the glue up. The also used to bleed people to get the bad blood out in George Washington's day. How much good that that do him? Check history.

If some is good why won't more be better. and most people tend to overdue ( original question, is there a formula for the gap you make? I did .013 on boards that are a final of 26" long. It might be a bit heavy.) Now we have to have a formula and measure the spring.

So back to another of my questions why do it, if it isn't necessary. And why put stress into the glue up in the first place. Correct me if I am wrong but don't the gaps get put in both faces?

And again did the extra work add any value? And it is a rhetorical question because the answer is no.

[Warren Lake]

I answered your statements, Ive seen non in 40 years in this trade licensed since 84. making up for not owning clamps is kindergarten level stuff. You should call SCM Invincible and Martin up, I think I read both of those machines have a lever to pull so the machine goes into spring joint mode. Important enough that high end manufacturers incorporate it right in the machine.

[Bill Rhodus]

I have the spring joint feature on my jointer. A lever allows the end of the outfeed table, furthest from the head, to sag. I believe a spring joint can be helpful as the ends of the board tend to shrink and swell more than the center.

[Warren Lake]

Bill what type of jointer?

I was just looking at an email from a Toronto dealer and looked at used machinery then saw Martin down the side. Watched a bit and sure enough they do have a handle. Most jointers table goes up and not tilt, says 1.5 so what is that referring to?

447684

[Mel Fulks]

I've never understood how the drop outfeed table of a "pattern makers " jointer could make a hollow joint. I can imagine no way beyond human skill ,and see that as highly unlikely. I worked in
a pattern shop for a couple of years .Old school German guy owned and ran it. He did not have a pattern makers jointer.
Patterns must have have slope to allow easy removal from the sand. I think a side slope AKA "draft" feature is more
likely how the pattern maker jointers were used. Shop had a big ,perhaps 36 " diameter precision disk sander with a
tilting table . That's how we did "draft". Such machines can be found on line ,for sale for use in pattern maker's shops .

[Joe Calhoon]

Warren, my Martin jointer doesn’t have the electronic readout but I think that is referring to depth of cut - 1.5mm. The spring joint is easy on the Martin and is very slight. I used to do spring joint on my SCM JP like you have by dropping in back from the end of the workpiece and pulling out before the cut finished. Then come back and make a full cut.
The old US straight line rips saws could also make a spring joint.
It’s a worthwhile operation that definitely adds value. Won’t show up right away and the customer will never know. Like a lot of stuff we do!


Bill what type of jointer?

I was just looking at an email from a Toronto dealer and looked at used machinery then saw Martin down the side. Watched a bit and sure enough they do have a handle. Most jointers table goes up and not tilt, says 1.5 so what is that referring to?

447684

[Bill Rhodus]

Bill what type of jointer?

I was just looking at an email from a Toronto dealer and looked at used machinery then saw Martin down the side. Watched a bit and sure enough they do have a handle. Most jointers table goes up and not tilt, says 1.5 so what is that referring to?

447684

Sorry to take so long to reply. I have an American 12" jointer. Outfeed wheel does move the table up and down while keeping it on parallel plane with the infeed table. There is however an additional pIr of cams with an attached lever that will allow the discharge end to drop.

[Mel Fulks]

Sorry to take so long to reply. I have an American 12" jointer. Outfeed wheel does move the table up and down while keeping it on parallel plane with the infeed table. There is however an additional pIr of cams with an attached lever that will allow the discharge end to drop.

That is interesting ,and I wondered about that. But decided it could not be that ,since they show wood too narrow to
benefit . Looks to me that Martin method would need some human feed skill. The slightly raised outfeed table method
makes a precise large arc needing only the right height lift ,pre straight-jointed boards. NO skill in guiding is needed to
run the board over the jointer beyond putting down-pressure .

[Warren Lake]

thanks Joe and Mel

Joe what is a MM :)

Im suprised those old Diehl and Mattison huge tank things I used to see at auctions that looked amazing then sold for 300.00 or some stupid way too low price. Had no idea should have looked at them closer at the controls and studied them a bit. Just want to be aware of stuff and I would have said logically they cant do that so thank you for mentioning that.

Mel you mean those big Old Wadkin sanders. One just sold recently up here and went for a good buck I think 3,500.00 plus buyers premium. What does Draft mean? I know the one where wind blows into your home.

[Mel Fulks]

Warren , Freeman and Kindt-Collins are companies that supply the pattern making trade. The disk sander we had was
made by one of those two. I think Kindt Collins. Don't know if Wadkin made them.
"Draft" is just slope to allow the pattern to be removed from the packed sand.

[Jim Matthews]

I know a few of you here do them any thoughts gap related to length?


Late to the party, but my approach is a little different.

I layup panels about this length.
I do this by hand, using the same plane each time.

It's about 9" long - less than 1/3 the board length.

If I take a shaving from the center, it will eventually "bottom out" and stop cutting.

The difference between the "highest" points at each end and the center is about 0.05 mm or .0019 inch.

Two boards laid up on edge get a gap about the thickness of one sheet of paper.

I leave the outermost boards proud, and plane them to final width after the clamps come off.

****

In practice, I do this to force the error into a repeatable position and assure the outermost edges are reliably tight.

[finlay gray]

0.013 would be hard to do.

[Warren Lake]

after the new knives on 27" I did .003. It clamped very easily and was fine, if anything it was still on the heavy side but if not not much so it lines up close to you .0019. These boards were 7" wide my originals were 2" wide. Final board widths will be 5 1/2" to 6 1/2".

[Rod Sheridan]

after the new knives on 27" I did .003. It clamped very easily and was fine, if anything it was still on the heavy side but if not not much so it lines up close to you .0019. These boards were 7" wide my originals were 2" wide. Final board widths will be 5 1/2" to 6 1/2".

Hi Warren, mine is setup for less, it’s 0:004” in about 40 inches (it’s 0.1mm in one meter)...Regatds, Rod.

[Mel Fulks]

We used a lot of white pine panels. With something that soft you can use more spring. I used as much as 3/32 on boards
About 42 inches long on the Ponderosa and North Eastern white pines. Even with 3 or 4 boards they pulled up and
stayed glued. Sometimes management , especially the roving geniuses clawing their way to fame, will want guys to
bring the material in from the cold and start gluin'. They know they will be in a "better place" when it all falls apart.
Ive seen guys trimming their fresh batch ....all the cut ends falling on the floor.....separated forever from their fellow
board members. Gotta' stop writin'.....eyes are gettin' misty....

[Warren Lake]

I learned the cold lesson on my own a few years before getting into this, I didnt get it as the outside didnt feel cold, The wood was still cold inside and the cold was coming back out, it was 8/4 pine and it open as the clamps came off. Good lesson before anything important. Also glue freshness, also stir glue. A Tech told me in the past if anyone tells you you dont have to stir glue they dont know what they are talking about and also after six months its on its way downhill. Tech from a top company and hes retired and guy there now very smart.

[Will Blick]

I know this subject has been beaten up for years on many ww forums, including here.
But I have to agree with Tom on this one.
IMO, lots of of these old school techniques were implemented for reasons that no longer exist today. Mainly, as Tom mentioned the incredible holding strength of modern glues.
I have never sprung a joint, I never had a failure.
That being said, with the tiny amount of a gap required, say 5 thou is my best guess based off this FWW video below, I doubt it will make much of a difference either way.
One of my issues with springing a joint is...
if your ends have more moisture then your centers when gluing, a spring might be helpful as possibly the wood would reach equilibrium after a finish is applied over all surfaces.
OTOH, if the ends happen to have less moisture when gluing (prob. rare, but possible, and yet its never suggested to check), I would think the spring joint is counter productive as if the ends increase moisture over time (more likely scenario), the added stress might cause end cracking. Prob. not in the glue joint, but in the wood itself.

Here is the video for spring technique with simple hand plane.

https://www.finewoodworking.com/project-guides/shop-projects/ep-1-panel-glue-ups-using-spring-joint

These authors are split on whether they serve any purpose....

https://www.popularwoodworking.com/article/three-ways-to-make-edge-joints-2/

I would love Franklin to answer this question with some serious testing like they do. Franklin does offer us some advise on recommended clamping pressure.

447910

For hardwoods which require 200 psi, the glue up on the video would prob. require a clamp about every 4", assuming about 400 psi per clamp. In the video, he uses one clamp in the center that is not even max fully tightened. This again demonstrates just how damn strong modern glues are. Franklin engineer at ww trade show once told me, its impossible to starve a joint of glue with pressure.

Also, when you see commercial factories make table tops... they rip saw and go direct into a glue up machine with very strong pneumatic pressure. I doubt those automated rip saws are springing the joints. A commercial table top maker would surely change their ways if the tops were cracking at the edges...

Bottom line here, aka my two cents.... I think glues are so damn strong today, it seems success can be had using any technique. But I would air on the side of more clamp force, vs. minimal clamping force as recommended by Franklin.

[Derek Cohen]

The main reason I add a very slight spring joint is that it is easier to mate two surfaces with a slight hollow than with two flats - it is so easy to add a slight bump to one flat, and this will force a gap at one end of a panel. Creating a spring joint ensures that the edges will mate perfectly.

Making a spring joint is - for me - best done with a hand plane. It could even be done with a block plane for extra control. Always check the joint between two boards first to ensure one has not inadvertently created the hollow when jointing!

Regards from Perth

Derek

[Mel Fulks]

It does add something... Long lasting work. Seeing bad panels in a new employment ,I told management I could stop
all the open at ends joints ,and did. Told all I would pay $20 for every panel I did that opened on ends. Heard replies like
"they all open up after some time". Many single jobs on large houses had over 100 panels. Some were exterior ,but that was before there were products like EXTIRA. I never had a claim , even though the bounty was open to all. Some of the
guys started making the family Sunday drives 'open end' treasure hunts. Good sound habits are what's needed ,not
capricious experiments. Even on paint grade work I do obvious grain matches .Obvious meaning, seeing at a glance.
Couple times clients who had ordered paint grade work changed their minds and decided to stain them! It was a compliment in a way...but I much prefer painted panels ....as they are generally seen as more formal. The power of
habit is strong. I've had people tell me a made some mistake, and I answered "no I did not" When they said "how do you
know you didn't make a mistake?"
"Good habits"

[Will Blick]

I dont have a dog in this battle...
but here is another very well written piece on why spring joints were very useful in the 1700's...but now???

https://www.woodcentral.com/woodworking/forum/archives.pl/bid/1001/md/read/id/474581/sbj/spring-joints-useful-or-not/

[Mel Fulks]

Will, I answered that question, but it was overnight. I won't ask you to read it ,but if you do read it and have questions
I will be glad to answer.

[Mel Fulks]

I'm not good at figuring out which questions are rhetorical and which are seeking answer .

[Will Blick]

Mel, I referenced a link that has a well written article...
I assume you feel the article is not accurate?
the article appeals to my common sense and my real world experience of not using spring joints. That does not mean, using a spring joint will create failure...that is not what this discussion was about.
I know u are a strong believer, but a high % of people are not...
as the article mentioned, table top manufacturers represent a powerful example that straight glue ups (no spring joints) don't fail. If they did, the makers would add spring joints....
Your experience with outdoor panels is prob. not a good reference for indoor furniture builds.

[Mel Fulks]

I read the article. It does not address the points I made. But since I'm helpful ,and a good sport, there are always well
written articles about everything... it's the ideas that are flawed. Now,I haven't read the articles listed below,but they might
be useful to those who want agreement ....and can't afford therapy.
Why Wash Socks and Underwear? New science says there are cures for VD and cologn is cheaper than ever!
Don't Give Up Your Seat On The Bus To An Old Lady ...Demonstrate That People Need To Save For Old Age!

[Will Blick]

Well, if you ever decide to read the article...
would be interested in your comments on it!

Give up your seat to an old lady on a bus?
Is there springs under her seat?
Is that the connection here? ;)

I remember a joke that is somewhat fitting here...
At Xmas dinner, the mom cut off the last 4" of the Ham before putting it in the pan for cooking...
the daughter asked her mom, why did u cut off the last 4" ?
The Mom responded, oh, cause my Mom always did.
They asked the Grandma, and she said, cause her Mom always did it.
The Great Grandma was there also, they asked her the same..
Her response...
cause I did not have a baking pan that was big enough ;)

I think a lot of this trickles down in ww.

[Mel Fulks]

Thanks,Will. I read it and posted about it. Here's another good read. New Study Says Self Immolation Saves An Estate
More Money Than Crooked Lawyers!!

[Andrew Hughes]

I once saw a pic of a table that was in a office one end sat next to a large picture window. The poster wondered why his glue joints on that side of table opened up. His little voice in his head said it was midday sun.
I agreed with most everyone that saw pic.
I think theres several reasons why ends will open up. Frugal woodworker trying to get every last inch when 3 inch should have been cut off. High Mc , long boards short bed jointer. Or just a unlucky spot for the table.
I will add a slight spring if my gut tells me to. Its not something I do regularly but then I don’t make many lately.
I also have one of the finest jointers ever made.

[Will Blick]

> 3 inch should have been cut off.

Is there any "rule of thumb" for this? I always cut the ends of my boards, but never knew how much to cut off... typically just a few inches. Am I being too frugal? Of course, if I see checks I go way past the check...

[Warren Lake]

so rip saws have a set up to spring, high end jointers have a set up to spring. They put a feature into the machines that costs, guess they must know nothing.

Read this site for 5 years or so and clear right away Mel had tons of time in the trenches and more so clear he understands wood.

Mel has added lots here and from experience, he is not a parrot. Differences on Jointer knives and types of steel, machining techniques and more.



Will whats your background? 30 years in this? Manufacturing? supplier to shops, custom shop??? one man shop?


Hobby guy with 400.00 hand planes ?

[Ronald Blue]

> 3 inch should have been cut off.

Is there any "rule of thumb" for this? I always cut the ends of my boards, but never knew how much to cut off... typically just a few inches. Am I being too frugal? Of course, if I see checks I go way past the check...

If you go to the sawmill and kiln drying forum you can find this information about trimming 3" off.

[Warren Lake]

if you buy good material trim the end 1" whatever throw it on the concrete floor if it breaks there is a crack you didnt see, then trim some more do the same, if it doesnt crack you are good to go. Once or twice found shakes a foot in but they were boards that were bad and had issues.

[Mel Fulks]

After I cut at least 2 inches ,I take that piece and use it to hit the saw table. If it easily breaks , I try again and take close
look. Then sometimes I can see the end of flaw. Not gonna glue up a panel that includes a board with a crack. Yes , I
waste a few seconds that some would use to adjust their radio or check email and web news.

[Joe Calhoon]

Warren,
here is what Diehl says about it.
https://diehlmachines.com/straight-and-hollow-cut/
Their gap is pretty slight. Sounds similar to what I get off the Martin jointer in spring joint setting. I have a small import SLR but have never been happy with the glue joint I get off that. It’s great for breaking down material for the moulder or further processing though.

[Brian Holcombe]

Springing compresses the ends of the board. The ends of the board lose moisture sooner than the centers and therefore are more likely to shrink and split. This compression helps avoid that, it also makes for better looking glue lines.

A plainly visible glue line is weaker than a truly invisible glue line and therefore the effort required to make the invisible glue joint (springing) is not wasted effort.

[Will Blick]

> Will whats your background? 30 years in this? Manufacturing? supplier to shops, custom shop??? one man shop? Hobby guy with 400.00 hand planes ?

Hi Warren... I thought this thread was about the use of spring joints? What is the relevance of all these personal questions as it relates to the use of a joint that has been around for 300+ years? In case you did not read all my posts, I was quoting other articles on this subject who are authorities in the field. Why not pose these questions to the author of those articles? Do u remember the old adage...

Attack the message...
NOT the messenger!

Very applicable in here...

[Warren Lake]

your tone to one of the most experienced guys here, enough of them have left. Guess you answered the question.

[Will Blick]

Just trying to learn Warren...
I thought that is one of the benefits of these forums?
Possibly I am not understanding the purpose of these forums?
I offer contributions, and appreciate constructive feedback from other members.
Sorry if my style does not concur with yours.
Regardless, I will remain civil and not redirect the discussion against any member personally, including you. That is NOT my style. I realize you feel differently and desire to turn ww issues personal against fellow members.
Now, back to the 300 yr old spring joint??

[andrew whicker]

I have never heard of this jointing technique until I read this thread earlier this week. It's an interesting idea, but I'm also confused by the necessity.

I have a few questions in the form of comments:

- It seems we are assuming the internal stresses created by this joint will stop the end of the boards from changing size. I don't understand why this would help. In all the cases of material movement I have dealt with (I'm coming from a metal machining / fabrication background), the correct design is to allow movement. Constraining movement doesn't work. I read Brian's comment that it 'squishes' the ends (my words, not his). How much does hand pressure compress wood?

- It seems that for some reason 'hand pressure' is the right amount of internal stress. No one seems to have any other type of explanation of what the proper stress is. Hand pressure is very low internal stress.

- I'm not sure how we would ever collect enough data on this subject to know the reasons behind cracks unless it's very obvious. A humidifier on one end of a big table top. A table that has one side finished, the other not finished. Etc. Do we know how this 300 yr old furniture was stored, lived, used, etc? Did anyone collect data on the moisture content along the length of the boards as they were building and kept taking data as the years went by? Were the pieces re-finished? Was the board's MC balanced when it was built? How did furniture builders 300 yrs ago decide the lumber was dry enough, etc?

- How does anyone's personal experience help me make a decision in this discussion? Even if you have 40 years of experience, wouldn't that mean we could only judge your first few years of work? Certainly work made in 2020 won't tell me anything about cracking 40 to 50+ years down the road.

- Why would I assume I could make a perfect ellipse along a 4 ft board with a low point of .005"? What about the local highs and lows? .005" is specification, but the local .008" or .003" isn't a concern?

- Overall, how do we know the reasons for failures (and, conversely, the reasons for success) of a piece that's been handled over 100 years?

Anyway, I think it's an interesting concept and I enjoy the topic and enjoyed thinking about it for the past days. It seems more or less like a belt and suspenders route than a necessary technique. I'm interested in giving it a shot, the articles I read also suggest it's a pretty easy technique to add to your building process. I'm sure I spent more time thinking about it than it would take to just try it and move on. I can definitely see it producing invisible glue lines, which I'm a fan of.

[Will Blick]

nice post Andrew, fully agreed with all your queries.
I also find the topic interesting.
As the link I posted previously.
Table top manufacturers IMO are the ultimate test to this methodology.
They make hundreds of thousands of table top glue ups, with automated rip saws moving directly into the automated glue machines then automated clamp system. With this volume of glue up tops over 50+ yrs, common sense suggest, they know better than any single woodworker that has built a few hundred panels in his life. If anyone has tested this scientifically, it would be these manufacturers, as they have the most to loose if their tops crack. Hence why I put credence in the authors position regarding table top manufacturers. I would think these manufacturers have run a lot of testing over the years. Unfortunately, any testing they do, would never become public knowledge as they want to maintain a competitive edge. Again, this addresses panel glue ups for primarily indoor conditions.
I also agree that adding less than 5 thou gap is not problematic with the incredibly powerful clamps we use today...heck, just normal jointing of boards will often have gaps like this, but prob. not centered.

[andrew whicker]

Thanks

but I do disagree with using capitalism as a metric for success. Capitalism learns the lowest cost way to provide the customer with the lowest bar of acceptable quality. I don't rely on our economic system to create high quality.

[Warren Lake]

Ill stick with the old guys, they told me enough ive never seen anywhere. Simple example was posting to not machine after sanding, post it here and told im wrong. Thankless. Old guys paid their dues and a lifetime and never steereed me wrong. They were about what they were taught and why, passed down from someone serious to someone else serious then add in the time spent running big stuff after a proper apprenticeship and production at mass level and more is learned. When you are running a shop with 12 stickers you are in the big leagues. When you send two boats to burma to buy teak to do city hall and have 36 other jobs on the go you will have some serious knowledge.

On the sanding I followed up after being told I was wrong (me not doubting the old guy) talked to two big companies. The first one my long time guy gone the new replacement copied and pasted something, hence my parrot statement. Checked with Hermes and answered by a pro. Happy there are still people still left in the industry that know what they are talking about. I once asked a wood expert how much material he has run on machines. He didnt answer. In school we had teachers who had degrees. We had some old europeans, they didnt spell well and had grammar issues though I should not talk. I was quick to realize someone with proper training in a top place at a top time to do an apprenticeship (after a town was bombed) knew massive stuff the education never taught.


I've done enough time to get stuff Mel and Joe and others have said that you will not find in books or the net teachers.

[Will Blick]

Well, I sort of agree...
its a balancing act with capitalism...
quality falls off so bad, Sales fall, which is the kiss of death for any business.
Also, warranty replacement is costly, and can sink a business if bad enough...
so quality must be high enough to prevent financial losses...
But in this case, its my guess, end cracks would take many years to appear, possibly way after warranty.

I was just looking at some bases I built from 1" maple almost 20yrs ago... quick jointed, sloppy glue up (its a machine base with wheels below, not furniture grade!), one layer of latex paint, peeled off in many areas, or nicked off.... never repainted them...not a single end crack in any of them. And they get exposed to all kinds of stresses a kitchen table top would never experience, in addition to changing levels of humidity constantly.
Like u pointed out, I am not drawing any conclusions from this, but nonetheless, shows how impressive glues are, specially thicker boards which offer more surface area.

[Mel Fulks]

Will ,the biggest stress is out doors, not the kitchen of a home with modern "climate control".
I would love to hear about and see stuff kept outdoors all the time. Wooden stuff ....not the charcoal grill.

[Mel Fulks]

Thanks

but I do disagree with using capitalism as a metric for success. Capitalism learns the lowest cost way to provide the customer with the lowest bar of acceptable quality. I don't rely on our economic system to create high quality.
If you live in USA you are getting higher quality and more choices. I think that translates to relying on Capitalism.
Unless you are ordering free stuff from 3rd World delivered by carrier pigeons.

[Will Blick]

> Ill stick with the old guys,

I am an old guy! But I will take info from anyone who has it.
I am an equal opportunity information "taker"!
If they are old, I don't assume they are right.
if they are young, I don't assume they are wrong.
I have seen it go both ways, in every field, not just ww.
In my field of engineering, I see old guys with wisdom as well as some highly outdated thinking and techniques which have long been superseded. I see some young guys with great innovative methods and systems and sometimes wisdom as well. Some are clueless.
I take every situation and evaluate it based on the facts and merits.
No "one size fits all" for me.
There is room for both of our methods of evaluation.

[Joe Calhoon]

Springing compresses the ends of the board. The ends of the board lose moisture sooner than the centers and therefore are more likely to shrink and split. This compression helps avoid that, it also makes for better looking glue lines.

A plainly visible glue line is weaker than a truly invisible glue line and therefore the effort required to make the invisible glue joint (springing) is not wasted effort.

Totally agree Brian. I have experimented doing glue joints off my import overhead saw SLR. It cuts straight and not capable of a spring joint. I can see the joint even though it is tight after gluing compared to my jointer made spring joint. Same with using my sliding table saw. It also makes a acceptable joint but still more visible than the jointed cut.

Here is another bit of info from Diehl about this. Advertising I know but I agree. I know a few larger quality custom furniture and millwork shops that have both gang rip and SLR and they use Diehl type SLR for edge gluing.
https://diehlmachines.com/wp-content/uploads/2012/09/why_rip-1-1.pdf

Another advantage of the spring joint for the craftsman is less clamps needed for glue up