Cut perfect mortise and tenon using a router


By all means, cutting wood by hand is a great recreational activity. But if you have a project that has to be finished at some point, whether it’s for your spouse or a client, hand cutting is simply not a fast or consistent enough method.

The perfect tool

One tool that most woodworkers have in possession is a plunge router. The cheapest most versatile tool you can buy. For this application the plunge router acts as a drill press, making a perfectly square hole in your work piece. 

Cutting a mortise using a router fence

One basic way to go about cutting a mortise with a router is to simply use a fence and a few stop blocks. The fence is there ro reference from the side to make the mortise straight and the stop blocks control the length. Take your time while setting this up, lay out your parts and draw on them to minimize the errors that so easily can occur. 

Make your own jig

Just using a fence on your router is all well and good but can be a bit wobbly. To make the operation more fool proof you can make a simple router jig. This increases the stability and accuracy of your mortise cutting. 

Cut a tenon using a router

All you need to make this is theoretically a stop clamped on your workpiece, set your router to the desired depth and cut away the material. Why I call this theoretical is because it’s hard to make consistent and repeatable. 

Make a tenoning jig

However the good thing is that a tenon jig is super simple to make, just need a few scraps of plywood or any other fairly good quality sheet material. 

What’s not shown in this video is that when you make the jig, leave the base for the router long. Choose the bit you are going to use and cut it to size using the router. Now you have a perfect indexing point when using the depth stop.

Professional mortise and tenon jigs

If you want to feel fancy and cut a lot of mortise and tenons, investing in a professional router jig might be the way to go. Once set up you can make perfect repeatable joints in no time. This can really make the difference if you are working on the clock or just want your projects to be finished at some point. 

The round mortise square tenon conundrum

There is one problem that often occurs when cutting mortise and tenon joints with a router and that is the round corners on the mortises. If you are picky, a round through mortise just screams that it’s machine made and doesn’t look as nice. The way to cure this problem is of course to square up the holes using a chisel. 

On the other hand, if the joint is not showing it really doesn’t make a difference but to route a rounded tenon you might need one of the professional jigs. 

Loose tenon

There is another way of making the mortise and tenon joint, and that is by using a loose tenon. This eliminates having to calculate the extra length needed for tenons. Just cut a mortise in both pieces and make a tenon to fit using the router table, equally as strong. 

But the easiest and by far the fastest way of cutting loose tenon joints is to invest in a Festool Domino. This machine can cut a day’s worth of mortises in ten minutes! So if productivity is an issue, this is a no brainer.


There are many ways to skin a mortise and tenon, as the famous saying goes. But to boil it down. If you want the joint to show, use a router and square up the holes. If not, get the Domino!