Thread: DIY Furniture: Dowelmax or Festool Domino?

Originally Posted by silentC

Are you basing that on your own reading, or on the quote you included?

Flat tenons, like the Domino, have a far superior gluing surface to a dowel. You have read that, haven't you? It has been mentioned a number of times now.

You seem to completely discount the results of at least 3 sets of tests presented that show the opposite.

I must conclude that you are trolling.

Originally Posted by US-Oz

No, from my ability to read and rapidly comprehend what I am reading, and an ability to use logic.

But you arnt interested on the views of experienced chairmakes. Tell me the real world difference between the stresses on a chair between M&T and Dominos? their isnt any in my opinion

Originally Posted by Geoff Dean

It didn't work.

You don't see the humor in someone supporting the Domino and castigating dowels because of their shrinking availability in hardware stores, when the tool he is supporting is completely unavailable in such stores?

I apologize if my sense of humor is too subtle for the hoi polloi here.

Originally Posted by US-Oz

I must conclude that you are trolling.

Pot-Kettle-Black

Originally Posted by Lignum

But you arnt interested on the views of experienced chairmakes. Tell me the real world difference between the stresses on a chair between M&T and Dominos? their isnt any in my opinion

But domino-joined chairs have been around how long?

In enough years their loose tenons will fail for all the reasons Hoadley gives.

Lignum, this is a geniune question, not an attempt at point scoring. Sorry I have to add that.

Why don't you get shrinkage in a traditional M&T?

I'm thinking of a tenon on, say, a quarter-sawn rail, where the lines of the grain are in the "short" or "cross" dimension. Won't the maximum shrinkage then occur across the tenon? And if so, what stops this shrinkage from causing joint failure ... just the increased surface area?

Originally Posted by US-Oz

But domino-joined chairs have been around how long?

In enough years their loose tenons will fail for all the reasons Hoadley gives.

Isnt one half of a M&T loose? Is that the half that dosnt fail.

And the Domino hasnt created a new join, just a new method of machining them. Loose tenon joinery on chairs has been around longer than you or me. They are every bit the equal to M&Ts

Originally Posted by US-Oz

You seem to completely discount the results of at least 3 sets of tests presented that show the opposite.

I must conclude that you are trolling.

Sigh....

A dowel mortice, because of it's shape, consists almost entirely of end grain. Surely you must comprehend that. So what you have is a mostly end-grain to long-grain gluing surface. This results in a weak glue bond. I hope you accept that because it is an established fact.

On the other hand, the mortice for a rectangular tenon oriented so that the long face is with the grain, as they nearly always are, presents mostly long grain. This yields a long-grain to long-grain gluing surface which results in a strong glue bond. I hope you accept that because it is, likewise, a well established fact.

So I conclude that a dowel presents an inferior gluing surface when compared to a rectangular tenon, all other things being equal.

This Dowelmax joint appears to base its strength on the tightness of fit of the tenon in the mortice, rather than providing a better glue bond. It relies upon using these 'high quality compressed dowels' to achieve this tight fit. If the tight it is ever diminished by shrinkage, which I also hope you accept occurs in ALL wooden objects, you are relying on an inferior glue bond to hold it together.

I resent having my contributions to this discussion dismissed as trolling. Try to keep your comments to the topic and above the belt if you can. I know it's hard.

Ron, I know the question was not directed at me, but someone else said in this respect that "I believe that historically M&T joints were subject to the same types of failure you have seen with dowels. That is why you see many old M&T joints made with pins. That way if the glue failed there would still be a mechanical connection."

I think the M&T joint will shrink and fail as well, but after a longer time due to there being no loose tenon, and then it is easily repairable with pinning etc.

Originally Posted by Ron Dunn

Lignum, this is a geniune question, not an attempt at point scoring. Sorry I have to add that.

Why don't you get shrinkage in a traditional M&T?

I'm thinking of a tenon on, say, a quarter-sawn rail, where the lines of the grain are in the "short" or "cross" dimension. Won't the maximum shrinkage then occur across the tenon? And if so, what stops this shrinkage from causing joint failure ... just the increased surface area?

A qtr sawn rail will expand top to bottom, A leg has 2 mortices both moving in different orentations. Some get to caried away and align the longest rail where the leg mortice runs the direction as that rail, thats the minimun movement on both. But its not an issue as the surface area of tenons is masive to that of a dowel so the percentages are on the side of the tenon to hold up a lot longer

Originally Posted by silentC

Sigh....

A dowel mortice, because of it's shape, consists almost entirely of end grain. Surely you must comprehend that. So what you have is a mostly end-grain to long-grain gluing surface. This results in a weak glue bond. I hope you accept that because it is an established fact.

The bond is actually created by the glue's adhesion to the surfaces, not by the mating of grains. With a modern glue the wood around the joint will fail before the join fails. With a multi-dowel joint the total amount of glue adhesion and holding strength of a joint is far in excess of the Domino tenons, as the tests show.

I hope you can accept that.

So I conclude that a dowel presents an inferior gluing surface when compared to a rectangular tenon, all other things being equal.

But you cannot compare one dowel to one rectangular tenon. Maybe that's where you are straying. That's not the Dowelmax model.

Originally Posted by Ron Dunn

Yeah, I know. That's why I said Morris-STYLE, rather than Morris chair. There are quite a few earlier Morris chairs which don't show through-tenon joinery, but they're quite square/chunky, and not as pretty as the later versions.

I will be using straight or bent arms, not curved, and I won't be using through tenons.

Good suggestion on the WIP.

I wish i even had a dowelmax for some of the joins in these. 512 hand cut mortices in the chairs and matching tables. Hard yakka

The bond is actually created by the glue's adhesion to the surfaces, not by the mating of grains.

Well, there we will have to agree to differ. It is not my understanding. Perhaps for some types of glue this is true, but not for typical woodworking glues. In fact, I can't believe I'm even having to debate it. I thought that anybody who has any amount of woodworking knowledge would accept this as fact.

I'm comparing any number of dowels to a flat tenon. They ALL have the same poor glue surface. Mostly end grain to long grain.

Hmmm, you don't understand modern polyurethane glues
http://www.vise.com.au/super_strong.shtml

eg:

# It is especially strong when applied to timbers being joined end-grain to end-grain
# Imagine the cores of the timber to be like drinking straws. Polyurethane glue will be drawn into these cores as it cures, expanding into them and creating an incredibly strong bond"