*Note* – This video was excerpted from an episode of TWW Live.
There are lots of methods available for making mortises. One of the most versatile tools for mortising is the hand-held router. You can do a lot with the manufacturer’s edge guide but you can do even more if you know how to design and construct simple jigs or guides.
I usually make my guides from scrap pieces of plywood or MDF and I use them in conjunction with guide bushings. Because I never quite know what bit/bushing combination I’m going to use, it’s a good idea to have a full set of guide bushings on hand at all times. I recommend the Rockler Guide Bushing Kit.
The key to making these jigs is to know the distance between the edge of the router bit and the edge of the guide bushing. Let’s say you’re using a 1/4″ bit and a 3/8″ guide bushing. That means you’ll have 1/16″ on each side of the bit for a total of 1/8″ difference. So if you’re designing a jig to cut a particular dimension, you should make sure the channel in the jig is 1/8″ wider than your desired mortise width.
You can use jigs like this for standard mortises of just about any size, as well as more fancy joinery like through mortises (an example I show in the video). Essentially, the sky is the limit. Best of all, you can make these jigs in minutes on the fly while working on a project. As long as you know your dimensions, you can knock a simple jig out in mere minutes.
Be sure to let us know what kind of mortising jigs you’ve made in the past. We’d love to see examples!