To make mortises to make mortise and tenon woodworking joints we have several options, from using a mortising machine, to using a router table, to the more artisan way of cutting the mortises by hand with a chisel and a wood mallet. But in this post we are going to see how I use the drill press as a improvised mortising machine to make a mortise in a very simple way. I just need the drill press and its table with the fence to lean the workpiece on which I want to make the mortise.
This is not a woodworking technique to use continuously, as the drill press can suffer. But it comes in handy once in a while to make a quick mortise in a piece of wood if we don’t want to do a lot of work with the chisel or set up the router.
The first thing I have to do is to decide in which position I want to make the mortise and tenon joint.
And, after making the wooden tenon, I have to mark the width of the tenon on the piece of wood where I want to cut the mortise. This way I have the length of the mortise I need to cut.
Now, with the help of a marking gauge, I mark the center of the edge the workpiece. I could also measure the width of that edge and divide by two to mark the center, but with the marking gauge I can mark from both sides of the piece so I can tell if I am marking exactly in the center of the edge or not.
So, now I am going to use the drill press as an improvised mortise machine to make the mortise in the marks I made. The drill bit I am going to use has a diameter equal to the thickness of the tenon. Yes, when making the tenon I made sure that the thickness of the tenon was equal to the diameter of that drill bit. This way I only have to adjust the side fence on the table of my drill press so that the tip of the drill bit coincides right on the line I made with the marking gauge. And I clamp the fence in that position. Like this I can drill overlapping holes between the marks that give the length of the mortise.
In this case I want to make a mortise and tenon joint where the tenon goes all the way through the wood. A through mortise and tenon joint. But as we can see in the picture, the vertical movement of this drill press is not wide enough for the drill bit to go all the way through the wood. But I was able to solve it by turning the workpiece over and drilling directly into those marks we see were left by drill bit tip.
And now, using the drill press as an improvised mortising machine, I move the workpiece to the sides to clean up the wood that was left between the overlapping holes I drilled. I have to do this because I don’t have a drill press mortising attachment that would make clean square holes. This involves inserting the drill bit a little, moving the piece to the sides to remove the wood, inserting the drill bit a little more and moving the piece to the sides again. I go down only a little at a time in order to avoid forcing the drill press too much when moving the wood sideways.
And so on until the drill bit can no longer be lowered. Because the drill bit does not reach the other side of the mortise, I have to turn over the workpiece and follow the same technique from the other side of the workpiece. Until I have a perfect mortise that goes through the wood from side to side.
Now I have two options, either round the corners of the wooden tenon or cut the corners of the mortise I just made to make it rectangular. And in this case I’m going to use a chisel to cut the corners of the mortise, to fit the wooden tenon I have made with its corners at 90 degrees.
Then, with the help of a wooden mallet I cut the corners to finish shaping the mortise into which the tenon will enter to make the wooden joint.
Here I have the rectangular mortise, with the corners I cut at 90 degrees with the chisel.
Now I can fit the wooden tenon to make this mortise and tenon joint. And in this case I have a through mortise and tenon T-joint in witch we can see the head of the tenon protruding the other side of the mortise. So I can get an idea of how tight I made this joint. And although it was not perfect, I’m sure that once I apply glue it will be very strong.