How do YOU lay out your M & T joints?

[Jason Scott]

Hey all,

I just finished up the lower rails on my coffee table yeterday which are all M&T joints. I have been laying out my joints for a while this way and am thinking there may be a better/easier way? I have read all about how to do it, but what seems to work for me is this:

1. I determine the width of the mortise (usually by which bit I am going to use on my router) and route a test mortise

2. I set the saw height and dado blade to cut a scrap tenon so it will fit snug.

3. I cut all the tenons.

4. I put the tenons flat on the piece where the mortise goes so I can get the length measurement for the mortise and mark it.

5. I route the mortise which is guided along a fence and just stop at the lines I made for length (should use stop blocks I guess but I don't)

6. Knock off the sharp corners on the tenon with a chisel and test fit

It goes well for me, but just wanted to know "how" most of you did it. It would certainly be easier with a mortise machine I think, but the router seems to work great. Thanks,

jason

[Glen Blanchard]

Well, I'm a loose tenon guy, so I am certainly no expert.....but would it not be easier if you cut the mortises first?

[Greg Hines, MD]

I always rout the mortises first. Then you can fit the tenons to it for a tight fit. I find that no matter how carefully I measure, I will make it too loose when I form the tenons first.

Generally 1/3 of the thickness of your parts is an adequate tenon thickness. So, for 3/4" stock, I make a 3/8" mortise and tenon.

Doc

[Bill White]

That you've pretty well got it down. I don't use the dado for the tenons. If there are just a few (say 4) I'll cut them w/ a tenon saw. More, I'll use the tenon jig.
Bill

[Jason Scott]

Thanks guys, Greg and Glen, I still am having a problem seeing how it is easier to cut the mortises first? Seems like 6 to one, half a dozen to another to me if you start by making test pieces to make sure it will all fit, am I wrong here? Bill, yeah I would like to get a tenon jig I think, but I just bought this nice dado set lol :)

[Glen Blanchard]

I have always just thought it would be easier to cut the mortise and then sneak up on the right fit by shaving the tenon as needed.

[Jim Becker]

Mortise first so I can fit the tennon to the mortise. The tenons can be cut slightly proud and then paired with sharp tools to fit with the appropriate snugness.

[Greg Hines, MD]

Thanks guys, Greg and Glen, I still am having a problem seeing how it is easier to cut the mortises first? Seems like 6 to one, half a dozen to another to me if you start by making test pieces to make sure it will all fit, am I wrong here? Bill, yeah I would like to get a tenon jig I think, but I just bought this nice dado set lol :)


I cut the mortises first because whatever you are using to cut them, router bit, hollow mortiser, or even the lowly chisel, is a fixed quantity. 1/2" chisel will cut a 1/2" mortise. By cutting the mortise first, you know the diameter you have to get to, and it is a lot easier to shave just a hair off a tenon than just a hair out of the bottom or side of a mortise.

Doc

[gary Zimmel]

Mortises first, usually with my dedicated mortiser.

To make the tenons, I start them with the TS and finish them up to fit perfectly with my hand planes.

[Mike Golka]

Like others have stated, mortise first. Its easier to make the peg smaller than try to make the hole smaller

[Greg Cole]

Laying them out I use the 1/3 rule mostly and do it with a marking gauge and knife. Don't think that's your question since everyone's telling ya how to cut'em.:rolleyes:
Mortise first via chisel & mallet. Tenon via table saw & jig slightly oversize and shoulder plane to fit "just so".
There's lotsa plans on the net for making a tenon jig.. although I'll admit mine is a Delta. I like the tenon jig just fine, but the mortise attachment for the drill press is not to my liking one bit.... ya can have it if ya want it.. but I'd suggest a dedicated mortiser and an "X-Y vice" if you do alot of M & T joinery.

Cheers.
Greg

[Sam Yerardi]

This is one of those questions like do you do dovetail pins first or tails first? And you can make a case for both. I've done both tenons first and mortises first. For me it depends on the particular M&T joint I'm doing like a rail into a stile versus a rail into a corner post. For a rail into a stile, I tend to do the tenon first and use it as a guide to make the mortise. For a corner post M&T I'll usually do the mortise first. Don't ask me why it's just how I do it. I won't say one is better than the other because I know I will prove myself wrong tonight when I go home to try it out :).

And by the way I usually do tails first ;). That should start a new thread...

[Bill Wyko]

With my Domino.:D I haven't tried any by hand yet. It's almost cheatin'

[Cliff Rohrabacher]

I use a slot mortiser to position them where I want 'em. I can usually hit my target within 0.005" without trying too hard and closer if I do.

Then I run some stock through the planar to tweak it just perfect - I like a tight fit on my loose tenons. If I'm in a finicky mood I'll make the tenons wide enough that I can rout the edges round to fit real snug otherwise I just blow that off and leave the empty space at the ends of the slots.

I found that tenon making on the saw is a supremely big PITA 'cause every error doubles. Hell if the temperature in the shop changes the metal expands or contracts and ~ ~ ~ ~

And I have discovered that loose tenons let me sink my mortices at whatever angle I want (like for chairs) and it's stronger than a tenon cut at an angle 'cause I never have to slice across the grain on the weak part (the tenon).

[Peter Quinn]

I am way better at subtraction than addition, so mortises first, tennons to fit regardless of loose/intregal or which tool I'm using to make the hole.

[Ben Rafael]

I've done it both ways.
It is easier to cut the mortise first because it is easier to trim the tenon to fit the mortise than to trim the mortise to fit the tenon.