Making Mortises Using a Drill Press

It’s always good to have more than one technique for doing stuff in woodworking. Here at the drill press, we can make mortises very similar to what we’ve done on the benchtop mortise machine. A couple of things are keys to make this work. One is the type of drill bit that you choose to use. I’m going to use a forstner bit. This is bit is quite a bit larger than what we need for our project but it’s easy to see than what forstner bit looks like. The beauty of a forstner bit is they drill a perfectly flat bottom hole which is handy for the mortise. What’s even better is that with forstner bits, you can actually drill a series of overlapping holes and that’s important so that we can get the slot, the mortise that we need in order for this joinery to work.

Here in the drill press, I’ve got a quarter inch forstner bit set up. We’ve got out mortise locations on the rail here. What I need to do is drill a series of overlapping holes from line to line. The fence is going to control the position of this board so that our mortises are perfectly centered. I’ve got my depth set to correctly match the depth to the mortise that we want to make.

Our next step is just to go ahead and drill that series of overlapping holes. On this first step, I’ve drilled four holes, one at each end of the mortise. That defines the length of the mortise that I’m trying to create. The two in the middle are a little bit more random. I’m not really concern about their placement but there is just a small bridge left in between these other holes. Now, I can come back with the forstner bit, take out each of these three bridges and that will leave my rough-cut mortise in here.

One of the things that’s note worthy is that this is quite a small forstner bit, so it’s hard for the chips to clear. It’s hard for them to come out, so you’ve got to give those chips a chance to evacuate out of the hole. Take it easy on the drill, so you don’t over heat it.

That second pass gives us our overlapping holes. You can see the high spots here, left behind by the forstner bit. Our next step, we’ll get the rest of the mortises drilled out then these pieces got to need to go to the bench where we can use a sharp chisel and remove the remaining high spots, so we have a perfect mortise.

The drill press is a pretty easy way to make our mortises. The downside is the high spot and each of these mortises that’s left behind by the overlapping holes that we do with the drill press. We need to deal with that, we don’t really have a mortise here yet. All we got right now is a series of holes. We have to clean that up.

I’m going to put the piece in the vice and now what we need to do is use good sharp bench chisel in order to pair these high spots down and smoothen out the walls of the mortise. One step, mortise wall is flat then we’re ready to move on to the next one. If you’re careful about pairing the high spots back to the circumference left behind by that drill bit; that will keep your mortises very similar in size which makes making your tenons a lot easier. Once this mortise is cleaned up, we just need to go on and finish the other five.