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box joint testing

Yes, I understand. By the time they meet you they are disgusted. They thought they paid for quality the first time around!

Reply to
Bill
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LOL, Actually you are correct. I guess I got caught up in Matthias (sp) surprise that the glue joint failed so quickly, but you described it spot on, Thanks

Still, as you say, the other joints were clearly superior and the finger joints as well with glue. I love all this learning, never felt so stupid in all my life.

Reply to
OFWW

It is 19/64" or 7mm. It is the micro 3 holer for 1" narrow stock or

1/2 " wood. It fits my normal Kreg Jig.
Reply to
OFWW

Yes, that's a good match; the Kreg-style step drills are certainly the right drills and countersinks for the compatible screws. Those (drill bits) are available (eBay) without the jigs, and the screws are well stocked lots of places.

Reply to
whit3rd

That size will probably be difficult to find round plugs to be filled with.

Reply to
Leon

OFWW wrote in news:nhl87blam8cac5qil6k02isjb9c1n5neli@

4ax.com:

Can't be done. Several groups have tested various joints in various ways over the years, and invariably come to the conclusion that there's too much variation in the wood used to resolve the difference between joints of similar strength. "Everything else being equal" just isn't going to exist with wood.

John

Reply to
John McCoy

The Kreg step drill bits are available at almost as many places as the screws. I've seen them at many WW stores as well as the BORG and Lowes.

Reply to
krw

Thanks for the info. I still wonder if there was a constant wide set of break points, on a certain day, with the same batch of wood, that some conclusion couldn't be made.

Reply to
OFWW

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Did a quick check, they make them and for flush trim they could be cut. Depends on how bad one wants them?

Reply to
OFWW

That's why statistics was invented, to deal with situations where there are multiple variables. Test 30 samples of each and calculate means and standard deviations and if there's a real difference it will likely show up.

Reply to
J. Clarke

OFWW wrote in news:2erb7b5q6826j2itao0ka18gmped2hqkd3@

4ax.com:

Well, that's a different question. You could certainly group results together, accepting that within some range of measurement error a group is "the same", and then look for differences between groups.

As I recall, when Fine Woodworking did their test several years ago, all the machined mortise & tenon variations were effectively the same (regular M&T, floating tenon, wedged tenon, etc). All of them were significantly stronger than dowelmax, beadlock, dominoes, etc.

I also recall there there was a difference in the failures, with the M&T always breaking the tenon, and the beadlock, etc, breaking the mortise. There was discussion at the time as to the significance of that difference, but I don't recall any conclusions.

John

Reply to
John McCoy

Shhhhh....

Reply to
Swingman

+1

I was talking to a GC around here who actually tries his best to do the highest quality work he can and cares about his clients and pleasing them.

He said the reason I'm seeing this so much is because the margins for a builder are often the same or less on a $650k home as they are on the $190k home. Both homes might be on 1/2-3/4 acre lots but the lot for the $650k home costs $350k and the house is expected to be 4x the size of the $190k house, have detailed trim-- chair, picture, 3 and 4 piece crown throughout-- recessed ceilings in almost every room, and a kitchen that looks like it's from the cover of a magazine, etc, etc. The man hours for building the bigger home are much greater, as well.

By the time the builder has done all this, he's set to make the same or less on the bigger house with the price tag 3.5x higher. He said this is why you get builders using particleboard cabinets in these giant homes because by the time you add up the hundred or more cabinets in these behemoth McMansions they can save $20k just by downgrading the cabinets.

Reply to
-MIKE-

Yeah that would be tedious. Like cutting small parts for boxes. l~)

Reply to
Leon

John, thanks for the info, I'll keep it all in mind, best I can, and use the info as I am working, while using the best common sense I can muster.

Reply to
OFWW

Jack wrote in news:n59804$ui8$ snipped-for-privacy@dont-email.me:

Assuming, of course, that "proper" includes using a suitable glue. Hot melt and cyanoacrylate being examples of unsuitable glues. Possibly also hide glue, depending on the type of joint.

"Strong enough" is probably true in most cases. I think a tenon which fits the mortise in both directions is stronger (and if I remember correctly FWW's test a few years back confirmed that), but it's probably stronger than it needs to be for most applications.

Something which takes a lot of racking force across a small joint, like a chair assembly, would probably benefit from a fully-formed tenon.

John

Reply to
John McCoy

On 12/21/2015 2:01 PM, John McCoy wrote: ...

I recall the article pretty well; I don't think this particular point was in the test matrix.

What was, best of my recollection was the loose tenon and standard and some minimal amount of testing for a "loose" vis a vis "snug" tenon in the mortise to illustrate a "good" and "not so good" quality of fitting the tenon but I do not recall the squared tenon in the rounded/routed mortise.

It's obvious from simple mechanics similarly to the obvious conclusion above re: a pocket screw that the should requires crushing the material to move whereas the open area requires "only" moving the glue with at least initial deformation of much less material for a given amount of racking displacement.

Reply to
dpb

John McCoy wrote in news:XnsA577993FFE3B5pogosupernews@213.239.209.88:

Other than cost, is there a reason CA glue is unsuitable? I'd used it on wood (not as a joint glue) and it does bond pretty well. Depending on the CA glue, you could get 30-60 seconds of open time. (Some of the thick stuff really needs accelerator or clamping.)

Puckdropper

Reply to
Puckdropper

On 12/21/2015 9:33 PM, Puckdropper wrote: ...

Historical "Crazy Glue" products are pretty brittle so don't do very well in shear. There are specifically-formulated cyanoacrylates for wood applications which pretty much perform as well as typical yellow wood glues...but other than the case for quick set-up times the cost is still pretty much the biggest case against it as a general purpose wood glue.

Reply to
dpb

dpb wrote in news:n59u4t$ofg$ snipped-for-privacy@dont-email.me:

Are we thinking of the same article? FWW has done two or three tests of that nature - according to the handy-dandy index, the one I'm thinking of was in issue 203 (and, of course, when I look at my stack of magazines, it goes 202 - 204, and 203 is nowhere to be found).

Anyway, I do recall M&T joints were found to fail by the tenon breaking, and while I don't recall if they postulated a mechanism for that failure, I'd worry that a short tenon would be more prone to break.

John

Reply to
John McCoy

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