Dados vs Dominos (DF500)

[Packard]

"The test consisted of a single vertical panel with a horizontal shelf supported from one side only. They would then load the end of the short shelf to see when it would fail. No glue was used and they were only interested in what mechanical strength was added by the joinery method."

That a "hung" dado joint fared poorly in the lab test should be obvious to anyone even with little woodworking experience because in a typical 3/4" sheet good, the depth was only 1/4 to 3/8" or roughly one-third of the material's thickness. There is no way a friction joint is good enough for shelfing or cabinetry.

In the practical world, no one would use dadoes without glue (some even toenail it in addition to gluing it) in cabinetry work if strength is desired. As such, the Association's test is of no to limited value to me.

Yes. But RTA furniture rarely calls for glue. And some kitchen cabinets are site assembled. Sometimes, from my experience using hot glue, or minimal glue. So to the manufacturers, valuable information.

I always used glue, but it seemed like much of the side to side rackingstrength was derived from the backing board. With the other preferred joinery, the joints contributed to the structure. I’m sure dominoes would have fared as well as dowels in the tests.

 

[Packard]

About 8 to 10 years ago, IKEA, who funded much of the RTA testing, came out with an entirely new joinery system that does not rely on glue.

They call it a “wedge dowel” and I was able to find a video on that. Not for sheet goods, but an interesting peek into the corporate mindset in RTA manufacturing.

 

[luvmytoolz]

@Packard Very interesting video!

I do like how they think outside the square.