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+-- Thread: Joint strength test (/showthread.php?tid=7365170)
Joint strength test - Timberwolf - 09-25-2021
https://www.finewoodworking.com/2009/02/25/joint-strength-test
RE: Joint strength test - muermon - 09-27-2021
Hi can you give us nonsubscribers the executive summary?
RE: Joint strength test - AHill - 09-28-2021
Not being a subscriber and not knowing the results, I wonder if there was any assessment of how good is good enough? It's quite possible for some applications, the worst performing joint in their test might be twice as strong as the application would ever require.
RE: Joint strength test - barryvabeach - 09-28-2021
I read the article when it came out, and first, they agreed that the test they did was only gluing a right angle joint and putting it under pressure till it failed - while an important test, it did not replicate multiple cycles of less force, such as a rail to stile in a door, or stresses that work in different directions, like a chair leg to rail. For straight pressure, bridle and half laps were the winners - presumably due to the glue area. Most of the machine created joints , dowels, domino, biscuits did pretty well as did mortise and tenon, and in general , thicker tenons did better than thinner ones. In some cases, the joint itself failed - like for the butt and miter, in most, the wood itself failed and fractured.
RE: Joint strength test - Wilbur Pan - 09-28-2021
(09-27-2021, 05:35 PM)muermon Wrote: Hi can you give us nonsubscribers the executive summary?
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I agree with Barry's assessment that their testing of joint failure is flawed because furniture doesn't fail because too much pressure is applied to it. It's the back and forth movements over time, like leaning back on a chair, or bumping into a table leg, plus wood movement, of course. I have a kitchen chair where the mortise and tenon joints popped loose (I didn't build it), and I and sure that it wasn't because of a cow sitting on it.
RE: Joint strength test - Tapper - 10-04-2021
This is an "interminable" discussion and debate. The part in the article that ALL joints don't have to be "bomb" proof caught my eye. For some applications biscuits will work just fine. I know this is pure heresy for purists here, but remains the fact.
Doug
RE: Joint strength test - AHill - 10-05-2021
Interesting also is that the test only considered right angle joints for door / panel frames. What about drawer carcase joints e.g. dovetails, lock-miters, etc.? What about joints that attach legs to carcases? To me, these are the joints that get the most abuse in service. Based on the joints tested, I'd say most of the joints listed would survive daily use.
RE: Joint strength test - rwe2156 - 10-05-2021
I know this article is 12 years old, but on the heels of Mr. Sullivan's infamous end grain strength test, maybe 2021 will go down as the year woodworking joinery got stood on its head?
Completely counterintuitive to me how a half lap joint can be that strong, but, hard to argue with the method - assuming the boards came from the same tree and have the same grain pattern.
90% of the time a tenon fails because it breaks, not because the glue fails to hold the joint together. It would make sense that pinned or wedged tenons would be similar in strength.
RE: Joint strength test - AHill - 10-06-2021
(10-05-2021, 09:25 AM)rwe2156 Wrote: I know this article is 12 years old, but on the heels of Mr. Sullivan's infamous end grain strength test, maybe 2021 will go down as the year woodworking joinery got stood on its head?
Completely counterintuitive to me how a half lap joint can be that strong, but, hard to argue with the method - assuming the boards came from the same tree and have the same grain pattern.
90% of the time a tenon fails because it breaks, not because the glue fails to hold the joint together. It would make sense that pinned or wedged tenons would be similar in strength.
Of all the joints listed, the half-lap and bridle joints have the most glue area. Makes sense to me. The butt joint ranking was the one that surprised me.