Mortise and Tenon Joints

[AlexSwansboro]

My next project is a box that will also work as an outdoor coffee table. I would like to use mortise and tenon joinery but I have struggled to make it work. I need some suggestions or advice on the mortise part. I am doing the tenons on the table saw and they seem to come out pretty nice.

I have looked at the Trend and Leigh mortise and tenon jigs and while expensive it seems to be my next step. Any advice would be appreciated.

Alex

 

[pviser]

I'd do the mortises first with a dedicated mortiser, then clean them up with a straight router bit and a template. Only then would I do the tenons on the table saw, leaving them very slightly fat, then do the final snug fit with sandpaper.

 

[MikeCSmith]

Good advice, mortise first, tenon second. It's easy to fix a tenon, not so easy to fix a mortise. However you do your mortise, router (I specifically like a router), or dedicated mortiser, or drill press; practice first so that you can get consistent with the mortise and then just make the tenons so they are just snug. Nothing to it. Good luck.

 

[CDPeters]

I do my mortises on the drill press with a forstner bit and fence and then clean out with a sharp chisel.

Use the fence on the drill press to keep the holes lined up straight and when cleaning with the chisels I like to clamp a 1 to 1 1/2" square block to the face of the workpiece, aligned with my layout marks to ensure the mortise stays square.

Agree with the others, do the mortises first then cut/pare the tenons to fit snug.

C.

 

[ehpoole]

If you are going to be making mortises with any regularity (e.g. you like arts and crafts, etc.) then my preference and suggestion would be to look into a benchtop power mortiser. You then size your tenons to match the mortise. A good benchtop mortiser can be had (used or new) for considerably less than some of the [more advanced] professional router-based mortising systems I have seen.

If you rarely make mortises, then a drill press, fence, and forstner bit coupled with one or two suitably sized bevel/bench chisels and a mallet is a good and easy enough way to go. Others will make jigs for their plunge routers (usually coupled with an upcut spiral bit) to cut the mortises, after which you can either square off the mortise or round off the tenon (again, the tenon will usually be sized to the mortise unless templates were used).

Ultimately, the real answer is whatever works for you. For me the benchtop mortiser is my usual go-to tool, for you it might just be a mortising chisel and mallet -- whatever works for you is the way to go.

 

[JimD]

I am not the most patient person and drill press + chisel or chisel alone do not work for me. I cannot keep the mortise uniform enough to suit me. I like a plunge router with a spiral upcut bit. I've used both a steel and a carbide bit for this. Steel obviously dulls quicker but will still make quite a few mortises. A straight bit with a bottom cutter might work OK. My favorite way to make these is with a template guide and a template. That takes a few minutes to make but insure uniformity. I have also put mortises in both pieces and then used a slip tenon. The plunge router makes the prettiest mortises and with good technique they are very accurate. They work best for fairly shallow mortises, however.

I also have a small dedicated mortiser - a Jet (but I don't think the brand is critial for this tool). For bigger mortises, especially if I don't want to make a little jig, this is my go-to tool. I also like the fact it does not involve using a screaming router. The mortises are not quite as pretty but they are sufficiently dimensionally accurate. This tool does not get used on every project but it makes things a whole lot easier when you need some mortises.

Jim

 

[Charles Lent]

A jig (even a home made one) and a plunge router with a spiral bit will make very fast and accurate mortises. You can then square the mortises off using a chisel or leave them with rounded ends,then make the tenons to fit on your table saw, or you could make mortises in both parts and then make floating tenon stock with your table saw and/or planer and then cut it to width and length to fit your mortises.

A Mortise Pal is good for making floating tenon mortises with a router, but you can make a jig that will work just as well. The tenon stock does not need to have rounded ends to fit the routed round end mortises. Most of the joint strength comes from the fit of the sides of the tenon to the sides of the mortise, so I have always left the 1/2 round area at each end of the mortise for glue squeeze out and have never had one of these joints fail.

I wrestled with the many older methods of making M&T joints for years. Mortising bits, bench mortisers, chisels, and table saw tenon jigs never really worked to my satisfaction and it took forever to fit the tenons to the mortises properly. Doing the mortises with a router worked much better for me. Floating tenons also worked well. Then I tackled a project that needed over 1700 mortise and tenon joints and I decided that I had to find an even better way. I bought a Leigh FMT jig and it saved me. M&T joints can be made with a perfect fit every time, using a router and an FMT jig. The FMT jig is expensive, but well worth it if you will have a lot of M&T joints to make.

Why do you want to use M&T joints to build a box? It would seem that box joints or dovetail joints would work much better.

Charley

 

[Bas]

When it comes to joinery, there are four factors to consider:
- Strength
- Setup time
- Execution time
- Price

Butt joints take no setup time, can be executed super fast, it's super cheap, but strength is marginal at best. On the other hand, mortise-and-tenon joints created with the Leigh FMT are very strong, short execution time, medium setup time and expensive. Mortise-and-tenon joints done with the drill press and chisel are very strong, long execution time, short setup time, and cheap. The Festool Domino excels in all categories except price, whereas the biscuit joiner is more or less average in all four. So take your pick on what's important.

Benchtop mortisers are pretty easy to set up and cut mortises quickly, but it does only that: mortising. A plunge router with jig is a little more difficult to set up (clamping/ support), but it's a more versatile tool. I like using dowels for my joints (Jessem jig). It's basically a bunch of small tenons into round mortises

I'm not a big fan of using the plunge router because it makes a lot of noise, and it takes so long to setup. Once done it cuts very quickly though. Likewise, the drill press + chisel method works, but after an hour of chopping, I start surfing the web and look at the Domino and Multirouter :tool: So basically I like something that's decent in every category, but it doesn't have to be great. Maybe it's because I have a short attention span oohhh tool sale at Lee Valley today shiny....

 

[Joe Scharle]

I'm a big fan of floating tenons which work well with routed mortises which works well with my Woodrat. I've got a dedicated mortiser, but use only for exposed mortises.

 

[AlexSwansboro]

I want to use M&T joints mostly just to see if I can do it. I am new to woodworking and have already done some pretty decent box joints. I wanted a new challenge.

 

[Joe Scharle]

A cheap way to practice is to get some BORG shelving (white pine), rip it in 2" widths and make little door frames. It's the practice that helps one learn to make flush fitting joints. Good luck, but above all....have fun!