Router Templates for Mortises Made Easy (& Accurately)

Jigs and templates are common in professional woodworking shops, as well as common topics in woodworking books, magazines and blogs. A good jig will do two things; make the work better and get the work done faster. If you get caught in the vortex of making the perfect, multifunction, micro-adjustable gizmo you may fill a few pages or impress your friends. But if making a jig takes longer than just doing the work, what’s the point? The jigs I use are generally ugly, unfinished and dedicated to a single task. Here is one of my favorites, along with tips to make it quickly.

One of the common myths about jigs and templates is that they allow you to do things you wouldn’t otherwise have the skill to do. Sorry, but that’s not true. It takes some skill and some care to make a good template. But you don’t have to work harder than you need to when you make a template.

In the photos I’m making a template from 1/2″ thick Baltic Birch plywood so that I can make a bunch of identical through mortises for a reproduction of a Gustav Stickley book rack. I’ll use the template with a flush-trim router bit.The bearing on the bit will follow the template and any errors in the template will show up in the actual work. I could lay out all the lines for the cuts in the template with pencil, but I already have a SketchUp model of the project. By printing out a full size pattern from the SketchUp model, and sticking that to the plywood with spray adhesive, I save a bunch of time and guarantee that the work matches the plan. I then use an X-Acto knife to cut away the paper that surrounds my mortises-to be.

It would be tedious and demanding to cut out the rectangular holes I need, but I can use the same method to make the template that the template will use on the work. I can use the router and the flush trim bit to follow a pattern. For these openings, I placed double-stick tape over the pattern (I use Speed-Tape, but you can find decent tape at most big-box home center stores). You want the pattern pieces to stick really well because if they shift at all when you run the router you ruin the work. Double-stick tape is pressure sensitive and if you smack things with a hammer (or squeeze it in a clamp) it holds better.

The first piece to stick down can be any size, the important thing is that the edge that will guide the router is nice and straight. A table saw cut is good enough, but it won’t hurt to run the edge over the jointer. The thin pieces between the mortises need to be the width of the intended mortise. That’s the theory, just remember if they are a bit smaller or larger than planned, the mortises will also be that size.

The short piece in between the two mortises is the only piece with a critical length, and again the real issue is that the length of that piece will determine the space between the mortises. The two holes are smaller than the mortise size and larger than the router bit. I drilled them before sticking the pattern pieces down, but they can just as well be drilled later on.

The last piece butts against the other pieces. It is far faster to build the rectangular openings than it is to cut them by hand. When the last piece is in place, the pattern is flipped over so that the guide pieces are down. Now I can take the router and drop the bit in the hole. When the bit is in place, turn the router on and run the bearing around the perimeter. You’ll be able to hear when the cut is complete. Turn the router off and wait for the bit to stop spinning before removing the bit.

After routing, the guide pieces are removed. The end of a chisel can be used to pry them off and if they are really stuck, a bit of lacquer thinner or acetone will dissolve the adhesive. The router will leave material in the corners of the template (and in the actual work). You won’t gain anything by squaring up the corners in the template, except for some practice. Some people square the template corners so they can use the template to guide the chisel for squaring the real mortises in the work. I don’t do that because the template makes it harder to see what is going on with the chisel. I just place the back of the chisel on the straight part of the cut.

The template lets the router follow any shape. In this piece there are rounded corners at the top, a decorative cut at the bottom and the inverted “D” shapes at the top. Those are all trickier to cut than the rectangular mortises, but the top edge of the “D” (and the short, straight sections at both ends of the “D”) can be cut the same way that the mortises are cut. The curve is cut with a jigsaw (following the full size pattern) and smoothed back to the layout line with a rasp.

On the actual workpiece, the template is clamped to the work and holes are drilled in the inside cutouts (to allow the bit to enter. The mortises are small enough to make the entire cut with the router, but the “D” shape is rough cut with a jig saw before routing. It is better to remove the material with light cuts from the router. You can hear it working but you shouldn’t make it scream.

The project I’m working on is a reproduction of a Gustav Stickey No. 74 Bookrack. It’s one of 57 projects in my book “Shop Drawings for Craftsman Furniture”.

 — Bob Lang