To build my radiator covers, I would like to use mortise and tenon joinery. Making the tenons using a router table and a jig seems doable. Trouble is that a mortise machine is costly. While I don’t have enough use to justify buying a mortiser it may just be that owning one would cause me to come up with more uses. So I acknowledge that a DIY mortise tailored for this specific use could be foolish if it were expensive or worked poorly. I do have an inexpensive floor drill press. My attempt to find a compatible mortise attachment for this drill press failed.
From the image you can pretty much see what I made. There are a couple of hold downs on the sides to secure the jig to the table. There are a couple of clamps that hold down the wood while I make the mortises. Clamps also hold the wood in the jig. Using the t-track to hold the bit straight did not work. Once I start up this project, I will provide more images of the fork like tool I used to hold the bit straight and also measure the distance between mortises consistently.
There is not enough power to cut deep mortises, but 1/2″ or so does work. Sharpening the bits is critical, so I have some cones to use on my drill. Otherwise, I sharpen them the same board I use for my chisels. I may try smoothing out the inside of the bits to help reduce clogs. With mortise chisels I can get deeper when needed.