An interesting question in one of the pro forums:
===== "I make some chairs using Festool Dominos. Is it ok to call the joinery "mortise and tenon"? I suppose a more accurate description would be loose tenon, but that sounds bad, like it's not secured.
And, yes, the chairs are sturdy. Sometimes you just need to cut wide slots and make bigger tenons and/or double up.
Thanks!" =====
I'm on the fence on this one.
Mortise and floating tenon.
That is what it is.... but can this guy call it a "Mortise & Tenon" joint in his brochure?
IMO, it is technically, a "mortise and tenon joint", and more traditionally, and specifically, a "mortise and feather tenon" joint.
Personally, I would not use the term "mortise and tenon" to advertise this type of joint without specifying the type of mortise and tenon joint.
If I wanted to be modern:
"mortise and floating tenon" as upscale said, or
If I wanted to more strictly traditional/technical:
"mortise and feather tenon"
I think that you would get more traditional structural and engineering agreement on the latter terminology.
That said, the ultimate enforcer would be probably a lawyer.
My guess would be "yes", but if he didn't qualify it at the same time with specific information about the Domino itself, he'd be doing a disservice to his own brochure. The Domino is such a new advancement to the home woodworker's art of tenon and mortise that without specific details as to how it works, many woodworkers would dismiss it as just another common tool.
Yes they are mortise and tenon but that is a floating tenon. In many cases that is NOT as strong in the long run as a true pinned tenon joint. The chairs are sturdy today but after 100 years of racking if they don'y have a pin through each side they are not 100% the same as what one would expect from mortise and tenon.
I would have to specify that it was loose tenon joinery.
I have trouble calling a piece that contains plywood, "solid wood construction" even though that is accepted practise. Plywood is the very best material for many uses and some parts of fine furniture, but I can't bring myself to call it solid wood.
basilisk
Actually a Domino makes a mortise. What you do with that mortise will determine what you call it.
I would certainly think that after 100 years of racking that a pin through the tennon would be worn out also. I don't buy that a pinned tennon makes a mortise and tennon significantly stronger unless no glue is being used.
=A0I don't buy that a pinned tennon makes a
We'll have to disagree on that one.
How could a pin make any difference if the joint were immovably glued together?
I'm with Leon on this one. In a glued situation, the pin is merely decoration.
-- "Human nature itself is evermore an advocate for liberty. There is also in human nature a resentment of injury, and indignation against wrong. A love of truth and a veneration of virtue. These amiable passions, are the latent spark. If the people are capable of understanding, seeing and feeling the differences between true and false, right and wrong, virtue and vice, to what better principle can the friends of mankind apply than to the sense of this difference?" --John Adams
In any case, I don't care if the joint lasts more than 30 years. I'll be dead by then. The people still living can make their own.
There is a mortise and there is a tenon. The fact that there are TWO mortises, with half the tenon in each one, in now way diminishes the strength or function of the joint. The DOMINO cuts mortises and you supply the tenon - store bought or shop made.
The joint IS a mortise and tenon joint and behaves like one, as opposed to a dowel or pair of dowels or a slots and biscuit.
Now if you were to say it was a Hand Cut mortise and tenon joint and you used a power tool to cut the mortise or tenon - Hand Cut would be deceptive.
NO chair joint will withstand a teenage boy - glued, welded, pinned or cut out of a single log - of oak.
If you're going to "pin" the joint - a square pin will hold up longer than a round pin. With modern glues however, a pinned joint is analogous to wearing a belt AND suspenders.
The beauty of the DOMINO and the mortise and tenon joints you can make with it is accuracy - side slop is minimal and top and bottom slop is as well - unless you want to "dial in" some slop.
Whether it's pinned or not has nothing to do with the joint being a Mortise and Tenon. And if the mortise and tenon is pinned together does it matter if there are two pins rather than just one?
As for strength - some woods used for high end furniture are not all that strong - mahogany for example, especially the stuff available today. It works beautifully - but a mahogany tenon won't be as strong as a separate straight grained birch "loose" tenon. And if the joint is an angled mortise and tenon joint, the separate, straight grained "loose" tenon will be stronger than a traditional tenon and won't split due to grain orientation
You are apparently using the wrong glue or making loose joints if you have so many failures. Other reasons can be: temperature too low during glueup, adhesive too old, adhesive previously frozen, or skinning time too long.
Good PVA glue joints make two pieces of wood into one. It's the surrounding wood which gives before the glue does.
Chairs are in a world of their own. Imperfect joints allow them to be assembled, and racking forces are more extreme than anywhere else in furniture, so there is a chance of glue failure. But it's the imperfect joint -gap- which causes it.
A glued joint is like grown wood: all one. If anything, the joint would be weaker due to the drilling. Check the joint strength test result for anyone this century and I'll bet you change your tune.
-- "Human nature itself is evermore an advocate for liberty. There is also in human nature a resentment of injury, and indignation against wrong. A love of truth and a veneration of virtue. These amiable passions, are the latent spark. If the people are capable of understanding, seeing and feeling the differences between true and false, right and wrong, virtue and vice, to what better principle can the friends of mankind apply than to the sense of this difference?" --John Adams
Agreed. There is a tendency (and I have it) to look at dovetail joints and automatically think of them as high craftsmanship. I know that most are done by a jig and router and not by a saw and chisel.
I think the same applies to the Domino. You can say it is a mortise and tenon joint, but not equivalent to one that is handcrafted.
MJ
We'll have to disagree on that one.
Thats OK and I still respect you. l~)
All valid points however.... What makes the pin "itself" rot, wear, or break proof. The pin is surely weaker than the wood that makes the tennon, if the tenon wears, the pin has to have worn to allow the tennon to move and wear.
I will give the pin the nod to perhaps helping a failed joint last 1% longer until the pin fails also.
Not that is NOT politically correct! Do you are? LOL
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