for people who do spring joints at times

[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/proj...g-spring-joint

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

https://www.popularwoodworking.com/a...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.

Pressure_Chart_10.jpg

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/woodwork...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.