Making Simple Templates for Guide Bushings

[Thomas McCurnin]

I did a search, and did not find an answer to this, which actually surprised me. I can't believe I'm the first to answer this question.

I am making templates for shallow mortises (1/8 deep by 1/2" wide by 2" long) using a standard Porter Cable guide bushing, not a bearing bit.

The width is not a problem as the mortise is close enough to a standard router bit size and I use a another standard router size for the OD of the guide bushing. So far, so good.

The length is a bit fussy. I have a written offset table that I use to add the offset to the template, which gets me pretty close. I usually make the templates out of scrap 1/4 MDF and make the template in my router table (using a plunge cut dropping the MDF on the spinning bit), but I usually need to run a whole bunch of test pieces (too long, too short, just right) and I either have to re-run them through the router table if its too long, or use a rasp on the slots to slightly lengthen them. I'm experienced, but plunge cuts on a router table still make me nervous, and sometimes the MDF moves, so I sometimes I get a sloppy entrance point.

What would be perfect would be some 1/2 baltic birch ply cut and glued into strips to form the slot the guide bushing rides in, but getting that to glue on on the edges firmly has been a problem. I've considered biscuits, or slots and spines, and pocket screws too. I've also considered 1/2" pine drawer stock (which would edge glue nicely) but I'd rather use plywood scraps if possible.

Of course, I cannot edge glue MDF.

How do you guys make your templates for guide bushings?

[Steve Wurster]

I have made some from MDF and plywood using pocket screws. The hard part with that of course is keeping things perfectly aligned since pieces have a tendency to move when driving pocket screws. What I have seen people do however is use CA glue (usually with an activator to speed up the process).

The trick is to make a spacer that's exactly the width you need (so for your case 2" plus twice the offset between bit and bushing). First you attach one of the middle pieces; keeping the overall surface flat is the key here. Next you put the spacer up against that first piece, and then you attach the second middle piece. That ensures the space between those pieces is exactly correct. Again, keeping the surface flat is the key.

[Ralph Okonieski]

I do as you suggest with 1/2 inch Baltic birch scrap pieces and glue up to make the template. I do not use a guide bushing, however. Preferred method for me is bearing bit. My templates are generally for a one or two time use. If needed for something to be used many, many times, I would probably make the same way except add splines.

[Phil Gaudio]

Here is a pic. of some templates I made to install a Lie Nielsen vise. Strips of 1/4" plywood glued/pin nailed to either 1/4" plywood or Masonite. These were made for use with a bearing guided bit. Worked great.

[Jim Becker]

Ralph makes a good point about using bearing guided tooling rather than a guide bushing. An advantage there is that sometimes a guide bushing isn't exactly concentric in the router base, no matter how you work to set things up. With bearing guided tooling the template is always the exact size of the recess you intend to route.

[andy bessette]

Mostly use pattern-following bits, whose patterns are dirt simple to make. However there are many cases where the desired radius is smaller than available pattern-following bits. In such cases I use a guide bushing, but in no case do I ever attempt to make a pattern slot the same size as the bushing; just keep the bushing pressed against the pattern, which I make from either 1/4" tempered Masonite of scrap 1/2" plywood.

[Max Neu]

As far as the plunge cutting issue your having,try drilling out some of the material ahead of time with a drill bit.That should alleviate the problem of the router bit wanting to grab the workpiece.

[Phil Mueller]

Not sure how many mortises you need to make, but I would think you could knock one out in about 5 minutes with a 1/2” chisel. I recently spent about two hours trying to figure out a router template for 16 mortises and ended up hand chopping them all in less than an hour and a half.

[Steve Fish]

This guy’s method might be worth a look
https://m.youtube.com/watch?v=RSW2ZSdyEmw

[andy bessette]

This guy’s method might be worth a look
https://m.youtube.com/watch?v=RSW2ZSdyEmw

Interesting method.

[Edwin Santos]

For what you are doing, I would consider making a jig with a long slot the width of the bushing. In this case, I would glue two pieces of 1/2" ply with spacers the size of your bushing to create the long slot. Then add stop blocks to the top using additional pieces of ply with slots and wing nuts to make the jig infinitely adjustable for the length of your mortises. If what I am describing is not clear, then google adjustable mortise jigs and you will see the basic concept which you can adapt for your task.

The video linked above kind of shows what I am talking about without the adjustable stops.

[Thomas McCurnin]

Not sure how many mortises you need to make, but I would think you could knock one out in about 5 minutes with a 1/2” chisel. I recently spent about two hours trying to figure out a router template for 16 mortises and ended up hand chopping them all in less than an hour and a half.


I spent 30 minutes making a template, test fitting, and gluing it up, and the clamping position did not work very well for a router. So, yes, I ending up making a shallow knife wall, accenting it with a .5mm pencil, deepening the knife wall with a small chisel, and chopping those rascals out, then cleaning up with a small router plane. The Paul Sellers Method, just like I was taught at school.

Sometimes old school is the best school.

[Tom M King]

I have some that are decades old, made from Baltic Birch plywood, with the wear edges hardened with epoxy. I made them before I ever saw a top bearing pattern bit, so they're made for guide bushings.

[Jim Becker]

Tom, if you use the super glue and painter's tape method for attaching your template, no clamps to get in the way. This has become a big thing in the guitar building world for routing recesses in bodies since there's nearly zero room to clamp a template with a small workpiece.