Making circles and cutting holes in wood can be accomplished in many ways such as ... the bandsaw, a jig saw, scroll saw, fret saw a hole saw, and even some others that are less common. Making circles or holes in wood is not always easy, depending on the tool, sometimes the circles or holes are not really round and very often the edges are quite rough, which sometime doesn't matter, but in some cases, and nice clean edge and a perfect circle are exactly what is needed.

One of the ways to make holes or circles is using a router fitted with a suitable straight bit. The problem with doing this with full size routers is that they are big and bulky and often the sizes of the cut-out can be quite small, which is exactly why I am making this Circle Jig for my Trim or Compact Router.

Making a Circle Jig is pretty easy and doesn't take that long to make, but there are some procedures to follow to make it easier to make and more functional ...

I started off by selecting some 'used" plywood that was 4 x 14 inches and 1/2 inch thick. Before I started making the jig I assembles all the parts, specifically the what was going to be the pivot point of the jig. For this I used a 2 inch piece of ready-rod that was ground to a point on one end and left flat at the other. The point with this is that I could use the ready-rod as the pivot point in either the pointed end, or the flat end if I wanted to drill and hole in my blank to allow it to sit in. Also secured a T-nut, a wing nut and a suitable flat washer and that was all the parts I needed.

The first cut I needed make was a slot down the center of my board that would be wide enough for the T-nut, but not too wide. For this cut I used my table saw fitted with a circular saw blade, details of which you can see in the video.

Circle Cutting Jig

The next thing to do was to make my jig look like a jig. In the past I have been responsible for inadvertently tossing, what were perfectly good jigs, into the scrap bin pile, so this one I made it too look like a jig so this won't happen. Made the outside of the jig rounded which will make it stand out, and, somewhat easier to use as well. After a bit of sanding to the outsdie after the bandsaw cut, the jig looked good and hand nice smooth edges, easy to hang on to.

Now came time to fit the trim router to the jig. I removed the base plate of the router to use as a template and laid it on  the jig to mark out where the holes need to go for the small bolts. After marking where the holes go, I used a very thin drill bit as a pilot hole, then flipped the jig over and used a small forstner bit to drill some countersink holes so the bolt heads would not protrude from the bottom of the jig. I then drilled the holes to fit the small bolts.

Once the trim router was bolted to the jig, and the pivot point parts assembled in the slot, the jig was ready to try out.

Circle Cutting Jig for a Trim Router

I started off by securing a 1/4 inch piece of scrap plywood to a backer board on my workbench ... set up the circle jig and started off by using the sharp end of the pivot point. I realized even before stating that the pivot point wants to be short in order to get a good, consistent cut. As you can see in the video, the circle jig worked well, even better than I hoped. It cut the plywood clean and made a perfect circle with surprising sharp, clean edges.

I'm very happy with this jig, something I know I will bet good use from in the future

Copyright Colin Knecht