Router Jigs for Cutting Perfect Circles and Ovals

There are literally hundreds of router jigs, from the simple straight edge guide to jigs for letter carving. Two of these jigs that you may or may not be familiar with is the circle cutting jig and the oval or ellipse cutting jig.

Circle Cutting Jig

A router circle cutting jig is a multipurpose device, it can be used with a router to make circles, round corners, even oval cuts. I'm

sure that there are many woodwork projects where router cut circles, arcs and ovals can be used but the best use, where I'm concerned is in cutting patterns that are themselves woodworking jigs.

Any router can make radius circle cuts but a small sized router, such as a little plastic laminate trim router is better suited for pattern making, because one can use the one-handed technique. One hand on the router and one hand the plastic jig arm to help stabilize it as you make shallow cuts.

After making a smoothly cut circle or oval pattern using the jig, one can rough cut the finish piece (1/4" or so from the finish cut line), then use a flush trim bit in a router to run along this pattern and produce a perfectly smooth, 90 degree (square) finish cut edge. Then, if you want a profile on the square edge, (ie. roman ogee), just use a roman ogee router bit that has a guide bushing to form the profile. What's more, you can use these patterns again and again.

Making patterns is an important part of my shop's operation, because the finish cut piece is only as accurate as the pattern used to create it and you only have to make an accurate pattern once.

Circle cutting jigs are not a new concept, they're available commercially and are simple enough to make. I found a good circle cutting jig for $69.99. This jig is made by Rockler and can also be used to cut and ellipse. It comes pre-drilled for mounting to routers with 6" base footprints. There is a bit of modification required in order to mount to a laminate trimmer. The maximum difference between minor and major axes is 8"; maximum length for major axis is 52". This jig is simple yet very effective.

Oval cutting jigs

I can't leave without mentioning oval cutting jigs. These are pretty impressive router jigs. Have you ever tried to draw a perfect oval or ellipse on a piece of paper? If so, I'm sure that you can appreciate the performance of this type jig. The difficulty of laying out an ellipse, much less cutting one lies in the fact that there are two radius's involved (major and minor).

A regular router circle cutting jig is used in conjunction with two controlled sliding centers. The plastic arm is held on two moveable pivot points that slide in dovetail channels that run perpendicular to one another.

Routers and the jigs that accompany them have revolutionized woodworking, they have enabled novice and beginning woodworkers around the globe to achieve some impressive technical advances. The #1 resource that I have used for the past 25 years in learning how to use and build router jigs is titled "Router Jigs & Techniques" by Patrick Spielman. It's a step by step handbook with an array of ideas, products and trade secrets. Some might say that this book is out dated, I beg to differ. The router jigs that I've made using the illustrations in this book are as relevant today as they ever were.

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