box joint testing

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On 12/24/2015 9:53 AM, OFWW wrote:
...[preceding discussion elided for brevity]...

Ya' lost me there...no idea how is intended to relate to current discussion.

US FPL (Forest Products Lab) has performed extensive tests on the question and concluded "no"; in fact, the test data shows that the higher the clamping pressure, the stronger the joint up to the point of physically crushing the material. I've posted links to this in the (fairly distant) past and unfortunately don't seem to have a bookmark at hand so will leave it at that for now, other than to point out the specific testing (as is virtually all work by the lab) was done in support of the production manufacturer of wood products, and doesn't really reflect a home-shop rec woodworker environment. Consequently, the pressures achieved at the upper limit there exceed what generally would be found in work rec.wooodworking participants shops. Which simply supports the bottom line answer of "No" is why I included the discussion. (Leon may be the one exception here with his known penchant... :) )
The key limitation in a quality glue joint as far as material prep causing poor adhesion (other than that of ill-fitting joints) is have a fresh, unburnished surface. If one were to, for example, joint the material with a set of dull knives it's possible for them to "hammer" the edge rather than cleanly slice the fibers. In this case the micro-pores that are critical for the bonding to occur can be closed and thus the glue simply lays upon the surface instead of actually forming the bond. I forget, it may be that Hoadley in his tome on wood discusses; I'm virtually sure it's in the FPL Handbook (all again I've not looked recently to confirm).
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Sorry, I was watching some lamination jobs and some Japanese big beams and how they were jointed. Just thought some of it was common to WWing.

Hmmm, the same pores for bonding that are also important for finishes and stains to adhere to. I think I understand that, so an overly "finished" joint can be a disadvantage and coarse sand paper the best when fitting?
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On 12/24/2015 8:56 PM, OFWW wrote:
...

Sanding isn't terribly effective but it's not particularly harmful, either. The ideal surface for a glue joint is one fresh off the plane or a chisel, say, after final tuning or a tenon for it's mating mortise. The sharper the tool, the better.
The problem outlined above is one that happens almost always with machine operations where the knives aren't kept sharp--this mostly happens because with a motor doing the work it's easier to keep putting of the sharpening past when "should have done" and since the knives are cutting in a rotating arc, when the dull surface contacts the material instead of cutting cleanly as when sharp it effectively hammers the surface. It's pretty common to see such burnished surfaces on commercial framing lumber from the planing operations as an illustration or in the mouldings in the box stores where the shaper cutters aren't changed out frequently enough...as you say, it'll really show up in the latter when finishing as differences in absoprtion and reflectance even if lightly sanded--it can take a lot of effort to remove the traces entirely. One's best off to select sticks that aren't so instead...
With hand tools, otoh, you need enough extra effort to make them work that one will stop and sharpen before reaching the point...or just quit! :)
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Thanks for the heads up, added to my notes.

I love sharpening my stuff and checking it out, like chisels against the end grain, and planes, planer and jointer. Just to see the ease of hand tools usage with the right edge is a thing of beauty to me. Even with router bits and saws. I love both power tools and hand tools and seeing the old planes and special purpose planes are a thing of beauty to me. Even the bench seats used for WW. I wish I could have done this from the beginning.
Got side tracked again. But thank you for your valuable insight and sharing your experience.
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On 12/24/2015 12:41 PM, dpb wrote:

In the early days of the web that was a great resource, now, with the psuedo wisdom of twenty something web designers, and left half bell curve government employees, that information from UPL is getting more difficult to locate lately.
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On 12/26/2015 11:38 AM, Swingman wrote:

That does seem true, unfortunately.
I've downloaded the Handbook and a few other goldies but didn't want to take the time to dig at the moment...
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The Web gets less and less useful as it gets more and more cluttered. I really wish Google would quit trying to be Microsoft and GM rolled into one and stick to developing their core competency.
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On 12/26/2015 12:28 PM, J. Clarke wrote:

Soon as the ComCasts, Verizons, AT&T's, et al got into providing Internet access and locked it down, and regulatory capture once again rules another public venue, the web has turned into a money grab, nothing more than a pallet for blithering millennial idiots to somehow "monetize" another one of their stupid ideas.
Screen real estate on your computer, once belonging to you, is now theirs, and by damned they're going to use it, and screw you. Even worse if you have a mobile device/tablet.
The asinine stuff is mostly free though, and the hive mind loves it ... even though their data and privacy IS the product. "Get off my lawn you blasted kids ... LOL
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On Sat, 26 Dec 2015 13:28:43 -0500, "J. Clarke"

Their core competency is their biggest problem. The other stuff they do might even be beneficial.
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wrote: >>The Web gets less and less useful as it gets more and more cluttered.

Google's core competency is making money off of advertising.
It is true that their search engine has become progressively less useful over the years - part of that is their fault (the recent idea that it should search for what it thinks you're looking for, rather than on the words you enter), but most of it is due to people gaming the system to try and get their site to show up first (there's a whole "Search Engine Optimization" industry that sets up bogus websites linked to each other, to try and make one look busy and important to Google).
John
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On Sun, 27 Dec 2015 14:35:31 -0000 (UTC), John McCoy

Sure, and that's the problem. Though I was specifically referring their search engine.

Their ranking has always been an issue (pay me for better ranking) but the fact that they're now the arbiter of truth makes matters worse. As I said, I've never trusted their search engine and it's only gotten worse.
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4ax.com:

I don't beleive you can pay Google for ranking (altho you can pay to put an ad at the top of the results, labeled as an ad).
But for facts (i.e. truth), now-a-days I go to Wikipedia. You have to be a little careful with what's there, but by and large it is very accurate.
John
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On 12/27/2015 5:38 PM, John McCoy wrote:

John,
While I agree that Wikipedia is a great source for information, no one should ever take what you may find there as "gospel"
The reason for this is that Wikipedia is a collaborative effort by the internet community (i.e. the very people who go to Wiki to seek knowledge).
Most posted there IS accurate but you don't want to be citing it as a source. Instead, use it as a "lead" to show you where (from the annotations there, if provided) to find the documented information you seek backed by authoritative sources.
Just as an example, if there was a Wiki entry for John McCoy explaining how you developed a strain of hybrid corn that was resistant to every known form of fungus that typically attacks the corn plant. I could come along and add additional information to your Wikipedia entry stating that in addition, you were related to McCoy family of the Hatfields and McCoys and that your great great grandfather was hanged for stealing horses shortly after the Civil War and that your grandmother missed the hanging since she was busy tending the family's bordello in St. Louis.
Classic Garbage In, Garbage Out
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I think this explains it nicely and in an easy-to-digest comic.
https://xkcd.com/978/
So basically Bonjour.
Puckdropper
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Make it to fit, don't make it fit.

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LOL. Actually, I could be related to the McCoys of the Hatfields and McCoys - there's a chunk of my great great great great grandfather's life we don't know much about (other than that he _was_ fleeing the hangman), it's not impossible he was part of the group that came to the US in the late 1700s.
You make a good point about using Wikipedia as a pointer to more detailed references, altho again you have to use some judgement as to the credibility of the reference.
But most Wikipedia articles get corrected pretty promptly when garbage is added. You can look at the history of an article, and see where people have added (either by intent or by error) bogus information, and, often only a few hours later, where it was taken out.
John
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On Sun, 27 Dec 2015 23:38:24 -0000 (UTC), John McCoy

That certainly depends on the subject. It's OK for (non AGW) scientific sorts of things. It's useless for anything were politics or any sort of controversy exists.

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Exactly. Like I said, you have to be a little careful. But controversial subjects aside, it's usually as accurate as any other source.
John
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4ax.com:

Depends on the glue. For epoxy, definately so. For common yellow woodworking glue, no, at least not with any kind of hand-tightened clamp. For other kinds of glues, I dunno.
It is, of course, very possible to not put enough glue in the joint in the first place, which would have the symptom you describe.
John
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On Thu, 24 Dec 2015 19:31:37 -0000 (UTC), John McCoy

I had heard in an online video once about over clamping problems, that they were going to do some tests of get info, but it never came about to my knowledge.
I had a couple half lap joints come apart which added to my wondering, but in the end I realized it was sloppy work on my part. Too loose a joint. I learned the hard way that if I cut a joint best to assemble in right then. Or store up some wood ahead of time.
I made a could half lap joints on 2 X 4's to put my metal Craftsman Cabinets on, checked out the fit and it was just a tad tighter than I figured it should be, just to get glue in there. Next morning I dbl Checked the fit and both were now a tad loose and when I added glue they really got sloppy. When the joints dried I could see a couple gaps. GRRRR. And the joint seemed like it was the easiest to do in the world.
I am great with sheet metal stuff, but wood working is far different. I would apprentice myself in a shop, for free, just to learn good habits and make some of this stuff natural to me. (and for now at least, I don't even mind sanding. :) )
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4ax.com:

Yeah, for common wood glues you need wood-to-wood contact for the glue to make a strong bond. The exception is epoxy, which will fill a gap (indeed, if you add sawdust or Lew's favorite microballoons (*) to make a putty, you can fill gaps measured in inches with epoxy).
Note that, while squeezing glue out due to clamping isn't an issue, scraping all the glue off during assembly is, especially when doing things like putting a tenon into a mortise. It is possible to make a joint too tight.

Construction lumber is a pain, because it changes shape and twists and what-not whenever you cut it. I'd probably have screwed something like that together instead of glue.

Yeah, I get that from watching my buddy the machinist. Seems like the big differences are that metal doesn't compress (so you can't make a joint a tad tight and push it together), and wood doesn't let you add filler (unlike welding metal).
John
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