Rounding tenons or squaring mortises?

A 10" flat bastard file and a little elbow grease knocks off the corners of a tenon for me.

YMMV

Lew

Everybody has their preference. On my current project (a simple desk table -- pictures coming in a couple weeks), I tried the rounded tenon approach on a couple of the joints. I decided that for me, squaring the mortise with chisel was faster and more precise than trying to round the tenons. So, about 1 1/2 tenons were rounded, the rest had the mortises squared.

Seems a little crazy to finally produce the perfect tenon (see pix), only to mess it up with a rasp.

Which way would be easiest for you?

The only time I think it makes a difference is if the tenon end will be exposed or even extend beyond the other face. In that case I would square the mortise.

YMMV.

Gordon Shumway

Our Constitution needs to be used less as a shield for the guilty and more as a sword for the victim.

I'm sorry, are these not going to be covered in glue and hidden for eternity?

If a router is used with a template that produces round-end tenons that exactly fit a round-end mortise, where is the lack of perfection?

How and why so?

I guess I don't get that. I found rounding over to be more difficult -- making sure that I didn't accidentally apply the rasp to the shoulder, leaving a notch that would be visible. In addition, getting the shape right seems to be hit or miss.

Your choice ... but factor into your decision the fact that your joint strength will basically come from the face to face surface glue area on the sides of your tenons and mortises, not necessarily from tenons perfectly rounded to fit the rounded mortise ends.

Precisely.

As to the relative strength of each, from a 1,000 feet, a flying red horse can't tell the difference.

Lew

In most cases the major face of a tenon is making long grain contact with a corresponding long grain mating surface in the mortise (and we all know that long grain mating surfaces make the strongest glue joints), whereas the narrow face of the tenon is usually mating with end grain in the mortise. Whether it really matters depends on the particular joint, but rounding the tenons does steal away a bit of the long grain to long grain contact, thus yielding a less than "perfect" joint. Personally, I always square up my mortises and tenons.

Hey! I promise I hadn't seen your post before I sent mine off. I just said basically the same thing using entirely different words. :-)

Hey, how do you spell the "raspberry" sound? :-)

Gordon Shumway

Our Constitution needs to be used less as a shield for the guilty and more as a sword for the victim.

Not to worry ... happens to me all the time!

Great minds ... :)

Somewhere in a dark corner of my mind I seem to remember a published test where rounded mortise and tenons actually fared better than squared.

What will really frost any anal about their M&T "fit" is seeing x-rays of some very sloppy old M&T joints in antique furniture, and from some of the more famous woodworkers.

Scare the hell out of you ...

Seems unlikely that would be true, but I guess stranger things have happened.

I would think it even less likely to hold true in the case where both faces of the tenon approach the same dimension, the worst case being an exact square where rounding the tenon yields a regular dowel joint. A square M&T joint is most certainly stronger than a dowel joint, but then it's a bit of an unfair comparison because a dowel joint is susceptible to twisting forces.

Yeah, but a mortise and tenon is a great joint to begin with, so even a sloppy one is reasonably strong. Still no excuse for crappy workmanship though! :-)

Easy, Use a router in a table and a round over bit. Oh wait... I use floating tenons. Never mind.

Easy, Use a router in a table and a round over bit. Oh wait... I use floating tenons. Never mind.

There you go, floating tennons. Round over bit for a tennon that is part of the end of a board, hard to do the entire length, the sholder will be the limiting factor.

Since you are already using floating tennons you should go ahead and buy your Festool Domino now. I have had mine about 2.5 years now and was not totally sure how much I would use it. Counting the tennons I have purchased and used so far I have cut nearely 2,000 mortises with the Domino. That is an average of about 16 mortises every week. You will find yourself using floating tennons more and more.

Come join Swingman and I down that slippery sloap. LOL

Sloap: A soap like material that is used on a slope to make it slippery. ;~)

Lol!! Good thing I wasn't drinking coffee just now.