Router Template Inlay

Routers can be used with an enormous selection of bits and after market accessories, a router has the capacity to perform a seemingly endless variety of tasks such as cutting rabbets, dadoes, slots, dovetails, finger joints, mortises, flush trimming laminates and veneers, routing decorative edges in wood, making moldings, carving, raising panels, etc. The list goes on and on.

One of my favorite uses for the router is inlay. Freehand inlay requires patience and skill and some people aren’t ready for it. That’s okay, for a nominal investment you can purchase an inlay kit, consisting of a 1/8” carbide spiral bit and a brass rub collar. The brass rub collar is an ingenious invention. It fits into the base of most standard routers, and is locked in place with a threaded ring that screws on. There is a centering post that comes with the kit, so install this first and then center the rub collar on it, locking it in place with the threaded ring. This exercise insures that the collar is concentric with the router bit, ensuring a tight fitting inlay.

Next remove the centering post and install the 1/8” carbide spiral bit. The way the rub collar works, is that it has a removable brass bushing that is held in place with an internal rubber ‘O’ ring. This brass bushing serves to compensate for the kerf left in the wood when you make a cut with the 1/8” bit. The brilliance of this idea is that this system allows you to use one template to create both the recess and the matching inlay.

The creative potential is enormous because you can design and make your own templates. The template thickness should be ¼” to match the length of the rub collar. I use ¼” MDF (medium density fiber board) because it is stable, inexpensive and it machines well. Making the template is pretty straightforward. Simply draw the design 7/32” larger than your intended design, all the way around the perimeter. Let’s say for example that you are making a jewelry box, and would like to inlay three 2” curly maple circles into the top. Take a piece of 1/4” MDF to the drill press and use an adjustable hole cutter to bore a hole 2 and 7/16” in diameter. This gives you a 2” hole enlarged 7/32 of an inch around the perimeter. Now cut a piece of curly maple 1/8” thick and double stick tape it to a backing board of 1/2” MDF. Clamp your template on top, remove the bushing from the collar and rout out the inlay. As you cut through, the double stick tape holds the inlay in place so it doesn’t get chewed up by the router. Repeat this two more times. Now lay out the three circles in pencil on the lip of your jewelry box and clamp the template on the first circle, carefully aligning it. Set the depth of the bit a little less (1/64”) than the thickness of the inlay, so that when the inlay is glued in there is some material to scrape and sand flush with the surface. Now put the bushing on the rub collar and rout out the recess. Repeat this on the other two circles, and then glue in the three inlays.

Now you’ve experienced the huge advantage of this system, which is the ability to quickly and accurately produce identical inlays.