Domino v MT joints

[David Handsman]

Hi. I am new here. I am considering the domino v the fmt for joinery. Let me know what you think.

Thanks.

David

[Peter Pedisich]

Domino only produces mortises, and you use the Festool tenons.
FMT produces mortises and tenons.
Domino is brought to the work piece.
You bring the work piece to the FMT.
FMT will do larger M&T than the Domino.

[Will Overton]

and you use the Festool tenons.


Or easily make your own.

[Darius Ferlas]

This is my intuitive take:

Domino style joinery relies on both members' glue joints, the MT relies only on on of those, while the other is an actual structural elements. I'd say that wherever the joinery is load bearing it would be better to use MT.

FMT will do domino style joints. Domino style jig won't do MT proper.

[Erik Christensen]

I have the domino (and really like it) and have looked at the FMT. I use the domino for things I do not think the FMT would even be feasible - mostly for cabinet case construction, attaching face frames etc.

The FMT seems more suitable for solid wood furniture construction and that is not the kind of projects I have lined up.

So for me the domino is the preferred tool - if I had a dozen chairs to make I might view the FMT differently.

[Will Overton]

FMT will do domino style joints. Domino style jig won't do MT proper.

That is a very good distinction.

I use my Domino often, but I still hang on to my mortiser and tenoning jig. I still like through tenons.

[Jerome Hanby]

I have the domino (and really like it) and have looked at the FMT. I use the domino for things I do not think the FMT would even be feasible - mostly for cabinet case construction, attaching face frames etc.

The FMT seems more suitable for solid wood furniture construction and that is not the kind of projects I have lined up.

So for me the domino is the preferred tool - if I had a dozen chairs to make I might view the FMT differently.

What if you had four chairs to make? I'd love to parley this next project into a new tool, but have this nagging monkey on my back that makes me need to actually justify it... I'm considering therapy ;)

[Erik Christensen]

Jerome

I think the domino would be a good choice for chair construction as long as the joints were concealed - if the design calls for a through tenon for aesthetics then the domino is not going to cut it.

I have on 2 occasions tried to dis-assemble a domino joined piece and on both occasions the joint was stronger than the wood.

Not that any of us needs encouragement to buy a new tool :D

[Greg Portland]

if the design calls for a through tenon for aesthetics then the domino is not going to cut it.This is my experience as well. The Domino joint has plenty of strength but you'll be giving up the aesthetics of exposed joinery.

[Justin Bukoski]

Jerome

I think the domino would be a good choice for chair construction as long as the joints were concealed - if the design calls for a through tenon for aesthetics then the domino is not going to cut it.

I have on 2 occasions tried to dis-assemble a domino joined piece and on both occasions the joint was stronger than the wood.

Not that any of us needs encouragement to buy a new tool :D

The joints I have made with the Domino are more than strong enough with todays modern glue. The only reason I use MT now is for aesthetics (ie through MT) and for that I usually want them square which IIRC the FMT does not.

[Steve Rowe]

I have both plus a slot mortiser. The domino is the goto tool most of the time due to the shear speed. Larger joints I use the slot mortiser. Small joinery I use the FMT. It will do larger joints but is much slower. Don't worry about strength, the wood breaks before the glue joint will in any properly prepared joint.

[Chris Padilla]

This is my intuitive take:

Domino style joinery relies on both members' glue joints, the MT relies only on on of those, while the other is an actual structural elements. I'd say that wherever the joinery is load bearing it would be better to use MT.

[can o' worms opened]
If you agree that modern glue is stronger than the wood then I would think, all things equal*, that the domino would be stronger than the integral tenon. The joint with the domino would have ~2x as much glue as the integral tenon.

*--the devil is in this detail here.

[Bill Huber]

This is my intuitive take:
I'd say that wherever the joinery is load bearing it would be better to use MT.

F

Why, a glue joint is stronger then wood, that is what everyone tells me, so would not all the glue around the loose tenon be stronger the a normal tenon?

[Peter Pedisich]

David,

I have built a homemade version of a mortising jig, shown here:
http://www.sawmillcreek.org/showthread.php?t=91686

It works well, but requires careful planning and setup, fine when you have
no deadline. I still have a Domino on my wish list...
One huge advantage of the Domino is it reduces setup time greatly, if this is important to you it could be the best method.

Good luck,

Pete

[Mike Henderson]

Tenons can be done easily and quickly on a table saw. Mortises are a bit more difficult. I use a Domino to make the mortises and my table saw to make the tenons. The Domino is smaller and can do mortises where a slot mortiser can't.

Plus, I can do loose tenons if I want to.

Mike

[Darius Ferlas]

Chris and Bill, modern glues certainly appear to be stronger that wood itself... but that statement cannot be accepted without any footnotes. I imagine that is why the manufacturer of, possibly the strongest glue, Titebond III states on the product's label "... Not for load bearing or structural applications..."

Pictures being worth 1000 words I'm including a sample. Both examples use identical members (thickness, width, length and gluing area). The load is downwards as illustrated by the arrows. Given that the load required can be handled by the lumber itself, which would you be more confident with? A or B? The glue will hold alright, but what good would that be if the wood under the glue did not?

Similarly, my intuition tells me that in structural applications a domino joinery offers only the strength of glue, or rather, the strength of the thin layer of wood under the surface of glue (cheek and the corresponding face). In a MT I have those plus the sheering strength of the tenon with its edge sitting on the bottom of the mortise.

I don't want to split hairs but there are certainly other factors to consider. For loads similar to those illustrated, in a domino the loose tenons have to be perfectly sized around their circumference (2 faces + 2 edges) to offer some structural strength of the material itself. Any wiggle room and you rely solely on the glue, or worse yet, on the weaker layer of wood under the glue.

With a MT it does not really matter. The tenon width might be a little less than the mortise length since the tenon will sit on the mortise's bottom and the sheering force required to break the tenon is unlikely to be less than the force required to break off the wood under the glue joint.

[mreza Salav]

Each has it's own advantages and disadvantages.
There are certain things you cannot do with one whereas the other one excells at:

As said, for cabinet making or things a like domino is incomparable to FMT. If you want to do tenons at the end of a long board FMT is not really practical.

However, there are situations where a loose tenon cannot be used, but a M/T joint can. As an example, think of small/thin spindles: you can make a small tenon at their end but a loose tenon isn't any good.

You have to see what type of work you do more to see which of them suits you better.

[Darius Ferlas]

I'm now confused. Are we talking abut techniques or about a products/jigs? I was leaning more towards the techniques and so I would not see any impracticality of tenons at the ends of long boards. Of course I wousd have a hard time to wrap my mind around making tenons at the ends of long boards using the FMT jig but I made them using a router for bed rails application, 75" long + 2 x (length of the tenon).

[Bob Landel]

I guess it is time for my two cents on a subject I have very little knowledge. I am still rather new to the hobby and consider myself an advanced beginner. Okay, maybe I really consider myself an intermediate.

To tackle mortising, I purchased (and returned) most of the inexpensive devices on the market:

HF free standing mortise machine
Drill press mortising attachment
Mortise Pal
JessEm Zip Slot
Leigh Super FMT (unnecessarily complicated long instruction booklet)
Rockler's "Bead.....whatever it is"
Rockler's router base with "squaring up pins"

After returning some of the above totaling above $800.00 plus, I bought a Domino! The clouds parted and the sunlight came streaming through.

Boy, is that machine easy and worth the money. End of story.

[Paul Johnstone]

Hi. I am new here. I am considering the domino v the fmt for joinery. Let me know what you think.

Thanks.

David

The FMT is a lot more versatile. Easier to make compound miter M/T.. Easy to make tiny M/T joints... The Leigh site had a ladder made out of matchsticks that they used the FMT for. I agree, that for making chairs, the FMT would probably be a better choice.

That said, the domino is faster and easier.. A lot better for the common tasks. The loose tennon sizes don't cover everything, but they cover a lot of applications. You can't make dollhouse furniture with a domino like you can with an FMT, but I think the average woodworker is better suited with the domino.

So the answer is... "It depends".