box joint testing

Happened to come across this test of Joints, not all types but a few,...and

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Our friend has a couple videos on it, he found with the wood he was using that the pocket screws, even with glue, was about the weakest, other than a butt joint with clue.

Now I am not going to argue his methods of measuring since he did apply the same test to all, however in reviewing what he did and his points about pocket screws, I sort of think a shallower pocket, in conjunction with a slightly longer screw might help tremendously.

So I am tossing out that idea for your consideration.

I would ask him, since he has the gear set up for testing to verify it for curiosities sake, but then if he did so and it all worked out then he should be paid for the proof I would think.

In any event, I do not think you will find any pocket screws in my new wall cabinets for my kitchen. I wish he had tested with domino joints.

What does your experience tell us?

Reply to
OFWW
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Hard to say here, I don't recall where the pocket hole joint method failed. Did the screws pull out of the mating side or did the end grain of the pocket hole piece fail. If the former, I agree with your thoughts. If the later, shallower pocket holes might be better. Anyway I typically glue pocket hole joints when I use them.

In my experience glued dowels and tenons and or floating tenons are better than screws.

But another black eye for TBIII. LOL

I have contacted Franklin more than a few times in the past 7+ years. My initial contact was to inquire on their position of the Wood Magazine glue test. Long story short TBIII did not do as well as TBII in the so called "Water Proof" testing. I did not recall the convoluted answer but they did send me a case of 4oz TBIII.

The a year or two back I learned that you must periodically shake TBIII to keep the ingredients thoroughly mixed. The agent that gives the glue a longer open time will settle to the bottom and if let to sit there for a long period will be extremely difficult to remix with out actually mixing, not shake.

There is also a shelf life on TBIII, and most bottles I see on the store shelves cut their recommended useful to 6 months or less.

And Now this test once again shows that the lesser yellow glue appears to provide a stronger bond than TBIII.

I think I am going back to TBII and or Elmers Probond or Gorilla White wood glue.

Reply to
Leon

Leon wrote in news:sqCdnXp snipped-for-privacy@giganews.com:

Wow, that's worth knowing. I haven't used TBIII until recently, but there is a bottle in the shop now. Guess I should shake it every time I walk past.

I think as you suggest I'm going to stick with plain yellow glue (or epoxy if I need waterproof).

John

Reply to
John McCoy

this is all very interesting. As I am fixing to build 10 more beehives for spring at will amount to about 160 box joints that will need to be glued up. I find the results of TBIII compared to TBII or the elmers quite a surprise.

Reply to
Steve Barker

I've found that pocket screws are stronger in harder woods and yes, longer is better. All this, however, seems a bit too much like common sense to me. :-) I don't think I ever needed a test to tell me that a glued joint is going to be stronger that a pocket hole screw. Sorry, I don't mean to offend anyone, but that's always seemed like a "duh!" to me.

Here's my verdict and why I use pocket screws. They're strong enough. I use them for joints and applications in which they are strong enough or even stronger. You don't always need a mortice & tenon joint, nor a dovetail, nor a rabbet joint. You don't always need glue. Some times a pocket screw is good enough. Some times it's better than good enough. And you know what? Some times it's perfect for the job.

And I certainly didn't need to see a test to tell me two pocket screws in soft wood are much weaker than a glued M&T joint. :-)

Reply to
-MIKE-

He did tests both with and without glue, very little difference, the glue let go first.

He did show the difference between screws both shallow and deep into the attached wood. Those that were deep, where you could almost see the tips, pulled the wood under the screw head free from the board with the pockets. If the screw was on the shallow side in the attached board then the board with the pocket was whole and the screw pulled out of the attached board. All material used was consistent on both sides.

His as well.

I used their stuff made specifically for melamine, didn't appear to hold or bond much better than TBII, without screws I wouldn't use either. Those shop cabinets are coming down after other projects are done, I'll use them for jigs.

Reply to
OFWW

Well I need to learn all I can, the glue verses screws test lost to the screws.

In pulling down cabinets in my kitchen I have been pulling them apart. They used dowels in the face frames with glue, after 40 years of sitting there the dowels mostly held strong, the glue and nail joints (or staples) were a mixed bag, it was surprising how much glue just gave up, where there was particle boards it was self destructing and stunk really bad.

Sometimes I wonder if it isn't just better all around to use horse glue, and epoxy for the tough stuff.

I'd like to see a test between the green machines M&T joint and a 3 dowel. Especially between a square tenon vs rounded with everything else being equal.

Reply to
OFWW

John, I used to also buy TiteBond Extend by the gallon. Same problem. I would transfer to a smaller bottle and it came out like milk. It worked fine but it sure was thin. Half way through that gallon it thickened to almost a pudding consistency. Talking to Franklin I learned that I needed to stir from the beginning. Try doing that!

Reply to
Leon

Shocking IMHO. FWIW the "Water Proof" classification on the TBIII bottle is deceiving. I looked that classification up and learned that no where in the description of the testing method did the words water proof show up except in the title of the classification. Only water resistance was used. Sounds like a good old boys agreement among those in that industry.

Reply to
Leon

I use pocket hole screws in 5 times more applications other than as pocket hole screws. It seems that pocket hole screws themselves are pretty darn good screws.

In another discussion the counter sink drill bits came up. I often use the Kreg drill bit to drill my countersink and pilot hole and then use pocket holes in those holes and then plug with conventional round plugs.

Reply to
Leon

IMO, it's the particle board that gave up. A glued particle board joint is only as good as the particle board, which we all know is about as strong as cheddar cheese. :-)

Epoxy on particle board is only as strong as the particle board, right?

But really, you already conducted the only *real world* test that has any relevance. You pulled down your cabinets and had to tear them apart, right? So glue, particle board, screws, staples, whatever combination of whatever they used worked for your cabinets. They didn't fall down, they had to be torn down.

Fast forward to today, however, and we've reached to tipping point. We have major cabinet manufacturers using a strange, soft, hot-glue mix on their cabinets and drawers in combination with long staples, and that $h!t's just falling apart en masse all over the place.

I may start a business that does nothing but repair and replace these crappy drawer fronts that are put together like this. I'm talking

1/2-3/4 million dollar homes using contractor grade cabinets built like this. It's disgusting... but lucrative.
Reply to
-MIKE-

I got sick of dealing with that and now I just buy more, smaller, bottles instead of trying to save money by buying one big one. Not worth the PITA to deal with stirring all the time. I'm on my last gallon and it'll be my last.

Reply to
-MIKE-

Ditto, ditto, ditto from me on everything you wrote.

Reply to
-MIKE-

To avoid issues like that, I think you might have to be your own contractor.

Reply to
Bill

I'm not sure who misunderstood whom. :-) I'm saying I'll start a biz that goes around to these homes and repairs these crappy cabs. I'm already doing this with other things in this area. I make a decent amount of money fixing stuff that the original builders did poorly or outright wrong.

In many cases, the homes are still under warranty from the builder, but the homeowners are so sick and tired of getting the run-around, blame games, or having the same people who did the crappy work to begin with come back to do more crappy work to "repair" their previous crappy work.... that they would rather *pay me* a premium to fix it and do it right than get it done for *free* by the incompetent builders.

Reply to
-MIKE-

Well, actually the shelves were cupped, on the wall units, one group of cabinets was sagging more and more, but the faces being oak were tough as nails, and the ends were Oak plywood and basically they were what was holding it all together. As you noted the particle board was all crap, crumbly, sagging and so on. And yes, the "real world test" was worth its weight in gold.

As a result I am wondering if 1/2" ply cabinet grade isn't just as good as 3/4" for my purposes, as 1/2" will support granite or whatever, and for shelving should last at least 50 years or until the next earthquake. :)

Seems like the cabinet doors are all stamped out like model A fenders around here, and they sell it as a kitchen upgrade using your existing cabinets. Found I make upgraded cabinets, increase the storage space by at least 1/2 and make it look really good for 1/2 the price of box store contractor upgraded doors alone. Give or take a little. Plus, for me it is fun.

Reply to
OFWW

Sounds like a great idea, I have both sizes of their pocket hole drill bits. And the smaller one sound good for certain things, and then you can make your own plugs in various styles. Good idea!

Reply to
OFWW

Yes, I buy quarts now. BUT the regular TBI and TBII should not be a problem. It seems to be more with the longer extend times that present the short life shelf life.

Reply to
Leon

I have not used the small pocket hole bit yet. What diameter is that? The standard size is 3/8" so cutting your own plugs is not a problem.

Reply to
Leon

No, it won. A proper glue joint is NEVER end-grain to long-grain, so a right-angle joint, glued, to compare to a right-angle pocket screw joint, would be mortise/tenon or box joint. Those, because the strain is spread over large area, allow the glue to hold. A simple butt joint, or even a shelf poked into a dado, affords only endgrain-to-long-grain surfaces mating, and we've all disassembled that kind of joint. It comes apart easily.

Reply to
whit3rd

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