Square the mortices or round the tenons?

[craigb]

I can't remember if we've already had this poll, apologies if we have (basically I can't be asred doing a search :o ).

Anyway, when cutting mortices with a router do you round the tenon or square the mortice?

Myself, I square the mortice.

I don't really know why other than I just like squared mortices. Even if it is more work than rounding the tenon.

[NewLou]

Yer I square the mortise to.......................A traditional mortise and tenon fit squarely is the strongest joint of this type.

REgards Lou

[Rocker]

The easiest way is to make the tenon octagonal, i.e. the two cheeks and three narrow edges at either end. This is very quick to do, and has the advantage of allowing excess glue to escape. That is, if I am not using floating tenons, in which case, I round over the tenon stock on the router table and then cut it to length. Theoretically, a square ended tenon would be marginally stronger; but I don't think this makes any difference in practice.

Rocker

[NewLou]

but I don't think this makes any difference in practice.

Rocker
Gidday Rocker:)

In practice this makes a considerable difference. A squared mortise and Tenon joint that fits snugly is considerably stronger than the kinds of hybrid/Short-Cut joints you have listed.

If its strength your after then a traditional mortise and tenon joint is the GO! Fine Woodworking MAgazine stress tested rounded mortise and tenons champhored tenons in a round mortise loose tenons and traditional M&T's.

Under stress testing traditional M&T joinery proved significantly stronger. All the other joint types failed well before the traditional M&T's. Much to the suprise of the testers I might add.

REgards Lou:)

[Driver]

I voted for Round the tenon because, on those rare occasions when I use a router to cut a mortice, the quickest result is the obvious choice.

I rarely use a router to cut a mortice, however, because I find either a judicious use of the drill press or a swift bash with a chisel and mallet does the job. Rounding the tenon is also the obvious choice after cutting the mortice with the drill press.

Col

[Lignum]

That is, if I am not using floating tenons, in which case, I round over the tenon stock on the router table and then cut it to length. Theoretically, a square ended tenon would be marginally stronger; but I don't think this makes any difference in practice.

Rocker

Agree 100% I use floating tenons that are router rounded, and as Rocker pointed out in practice (real world day to day practice) the difference would be so slight it wouldnt matter. In 3 weeks ill have my new Domino and rounded loose tenons will be all ill be using:D

[Rocker]

NewLou,

I would not argue with you, or with FW for that matter. I merely maintain that it is rarely necessary for the joint to have the maximum possible theoretical strength; and that, if a rounded or chamfered tenon has only, say, 85% of the strength of a square one, it is normally speaking still plenty strong enough for its purpose.

Rocker

[NewLou]

Rocker

Totally agree if the joinery is there simply for looks its a no brainer. However if the joinery is being used for a WorkBench or the like where Constant stress is a consideration Then the strongest joint I can use is my preference.

Even then I'm inclined to reinforce it with pocket holes or my own epoxy castings! (But thats just me)

REgardless It is interesting to have some kind of reference point in regards to the structural integrity of this kind of joinery........suprisingly the difference is significant

REgards Lou:)

[Lignum]

Lou what is the FWW issue you have? I have FWW No 111 PG: 59 all about joint strength, and its surprising. These are cabinet doors and both loose tenon and mortice and tenon and under 1,200 psi started to open and snaped at 2,700psi and the surprise was two and three biscuits, the gap started at 1,700psi and snapped at 2,800 psi for the twin bisc and 3,000 for the tripple. So biscuits are the strongest for doors acording to that article

[NewLou]

Lig:D

I was reading up about joinery on the FineWoodworkingNetwork for my workbench. I'll see If i can find the article again. In this particular test I'm pretty sure that the Biscuits proved the weakest type of joinery. IF interested I'll dig it up again and get some test specs

.....................Is always interesting for future reference.

From Fine Woodworking #148

TRADITIONAL TENON

Strength: Superior
RAte of Failure: Gradual
Strength after failure: Superior
Rigidity: Very stiff

Round Edged Floating Tenon

Strength: Excellent
RAte of Failure: Gradual
Strength after failure: Excellent
Rigidity: Stiff

Straight Edged Floating Tenon

Strength: Excellent
RAte of Failure: Abrupt
Strength after failure: Excellent
Rigidity: stiff

Twin #20 Biscuits

Strength: Good
RAte of Failure: Gradual
Strength after failure: Good
Rigidity: Moderate

This is a great little summary of the outcomes

REgards Lou:)

[Wongo]

Round the tenon cos I do it my way:cool:

[Grunt]

I do it Wongo's way.

[Skew ChiDAMN!!]

Like driver and for basically the same reasons, I round the tenon. I'll also start the mortice using a bit'n'brace with a squaring jig if I'm feeling a tad darkside... besides the chisel, that's about as darkside as I want to get, too... Oh, for a powered morticer! ;)

[silentC]

Totally agree if the joinery is there simply for looks its a no brainer.
How can a mortice and tenon be there simply for looks? You can't see it!! :rolleyes:

I usually round the tenon if it's a mortice cut with the router. Have squared the mortice in the past when I'm being fussy.

I recall the results of another one of those 'tests'. They were specifically testing doors. The biscuit join was the strongest but it failed suddenly and completely. The mortice and tenon failed sooner but it hung together for longer.

[outback]

I'm a round tenon. :p

[Wongo]

It is landslide victory. Today is a great day for all of us tenon rounders.:D It has proven again that we are far more superior.

Sucked in mortice squarers.:D

[Grunt]

So we have the 'Dark Side' and the 'Light Side' and now the 'Rounds' and the 'Squares'

What about the people who use biscuits?

[keith53]

It is landslide victory. Today is a great day for all of us tenon rounders.:D It has proven again that we are far more superior.

Sucked in mortice squarers.:D

Scott,

What about those of us who do both? I knew I should have voted each way. :confused: If I do the mortice with the router I round the tenon. If I use the morticing attachment on the drill press, I square the tenon. I tend to agree with Rocker though. Besides, with the glues available nowadays it would be rare to subject a joint to its maximum pressure.

Cheers,
Keith

[echnidna]

Lig:D

I was reading up about joinery on the FineWoodworkingNetwork for my workbench. I'll see If i can find the article again. In this particular test I'm pretty sure that the Biscuits proved the weakest type of joinery. IF interested I'll dig it up again and get some test specs

.....................Is always interesting for future reference.

From Fine Woodworking #148

TRADITIONAL TENON

Strength: Superior
RAte of Failure: Gradual
Strength after failure: Superior
Rigidity: Very stiff

Round Edged Floating Tenon

Strength: Excellent
RAte of Failure: Gradual
Strength after failure: Excellent
Rigidity: Stiff

Straight Edged Floating Tenon

Strength: Excellent
RAte of Failure: Abrupt
Strength after failure: Excellent
Rigidity: stiff

Twin #20 Biscuits

Strength: Good
RAte of Failure: Gradual
Strength after failure: Good
Rigidity: Moderate

This is a great little summary of the outcomes

REgards Lou:)

SEEN THAT ---- BUT THE TESTS WERE FLAWED
It did not show test results of the same joints without glue.
Then repeat the tests with various glues

As glue deteriorates such tests would show the likliehood or not of furniture becoming an heirloom or antiquity

It would also be interesting to compare properly designed dowel joints in the same tests.

[silentC]

Keith,

The question posed by the poll assumes that the mortice was created with a router. Otherwise, there is obviously no alternative but to produce a square tenon. Biscuits don't come into it either.

What the poll is saying is: of those of us who make mortices with a router, when we do so, four people square off the ends of the mortice to take a square tenon and twelve round the tenon ends to suit the mortice.

[keith53]

Keith,

The question posed by the poll assumes that the mortice was created with a router. Otherwise, there is obviously no alternative but to produce a square tenon. Biscuits don't come into it either.

What the poll is saying is: of those of us who make mortices with a router, when we do so, four people square off the ends of the mortice to take a square tenon and twelve round the tenon ends to suit the mortice.

Yep, point taken...:o

[Driver]

What the poll is saying is: of those of us who make mortices with a router, when we do so, four people square off the ends of the mortice to take a square tenon and twelve round the tenon ends to suit the mortice.

silentC the psephologist! :) (with a silent p, of course).

[silentC]

I beg your pardon, what did you just call me?!!

I was an assistant poll clerk at the North Sydney council elections one year. Does that count?

[Driver]

I beg your pardon, what did you just call me?!!

I was an assistant poll clerk at the North Sydney council elections one year. Does that count?


I don't know whether or not that counts but what may be more important (for democracy in North Sydney) did you count?

[silentC]

Not allowed. That was the Poll Clerk's job. All the assistant Poll Clerk was allowed to do was tick off names. :rolleyes:

[Driver]

Not allowed. That was the Poll Clerk's job. All the assistant Poll Clerk was allowed to do was tick off names. :rolleyes:

So - if you didn't count, did that make you a no-account? :cool:

[silentC]

By all accounts, yes ;)

[mic-d]

When I've had round mortices I've done both methods. I quickly discovered that with a tenon 20mmx42mmx42mm in spotty gum, that rounding the tenon was much much faster than squaring the mortice. I haven't been called back so I assume the gates I made are still swinging.;)
I wonder what result we'd get to a poll on how people cut their round-end mortices. Currently I use a drill press and forstner bit. I'm sure I will use a router when I finally get around to making a morticing jig.

Cheers
Michael

[outback]

I think the beans you've been counting have a little fungus or something growing on them, it has affacted you, in a very sad way. :D

[craigb]

I think the beans you've been counting have a little fungus or something growing on them, it has affacted you, in a very sad way. :D

To whom is this observation addressed outback? :confused:

[outback]

To whom is this observation addressed outback? :confused:

Silent and Driver, the accounting counters, counting counts countingly. :D

[silentC]

Yeah but your opinion doesn't count :p

[Wood Borer]

I do most of my mortise and tenon joints using darkside methods - mortice chisels, handsaws, shoulder plane(s).

I occasionally use an electric router for the mortises.

At all times I square the mortises and the tenons.


As has been stated many times before, I do woodwork as a most enjoyable pastime so the little extra effort is all part of the pleasure for me.

If I was making pieces commercially, I would take shortcuts that hurry the job along but don't compromise the quality.

[Caliban]

Silent and Driver, the accounting counters, counting counts countingly. :D
but counts are useful!

I beg your pardon, what did you just call me?!!

Darren don't start that yankie phobia all over again or we'll have another rash of Outback wondering if he's one.;)

[doug the slug]

How can a mortice and tenon be there simply for looks? You can't see it!! :rolleyes:....

True, in most cases, Silent. But what about a through tennon, maybe with a wedge in it for a knockdown bench or just for decoration in a coffee table etc? how many of you will round the tennon in this case.

for the record,i used to be a "round the tennon" man, following George's advice on the triton dvd, but now i follow martin's advice and square the tennon, cos its far more accurate to do, and nearly as quick. it results in a much better jointhttp://www.woodworkforums.ubeaut.com.au/images/icons/icon14.gif

[silentC]

True, in most cases, Silent. But what about a through tennon, maybe with a wedge in it for a knockdown bench or just for decoration in a coffee table etc? how many of you will round the tennon in this case.
Yes but it's not just there for looks is it? It's a practical joint that has been prettied up.

Rocker said:

I merely maintain that it is rarely necessary for the joint to have the maximum possible theoretical strength; and that, if a rounded or chamfered tenon has only, say, 85% of the strength of a square one, it is normally speaking still plenty strong enough for its purpose.

And Lou said:

Totally agree if the joinery is there simply for looks its a no brainer.

Which, as far as I'm concerned, makes no sense at all because you can't see the tenon in the situation that was being discussed. But I don't know why that surprises me.

And yes I have seen through tenons that have been rounded ;)

[corbs]

I am currently in the process of making two loft beds for my young lads and have nearly finished the ends which consisted of 48 mortice & tennon joints. As I am lazy I have made the mortices on a jig and used a 19mm router bit to make through mortices, I then made the tennons the correct size for a squared off tennon and then rounded them off with a 7.5mm round over bit. There is a small amount of rasp work to do but a hell of a lot less than cleaning out the mortices with a chisel. To add some strength and add a decorative touch to the beds, I am going to wedge the joints. Standby for photos of the finished product in the next couple of years. :o:rolleyes:

Corbs

[holzman]

Definitely square for me. IF i do it then i do it properly.