How to Cut Circles and Ovals with a Router (Circle Jig Guide)

Infinity Cutting Tools |

Oval & Circle Cutter with Vacuum Base

Use your router and our new Circle & Ellipse Router Jig to make circles from 24-1/2" to 90-1/2" in diameter or ellipses from 24-1/2" x 33-1/2" to 81-1/2" x 90-1/2". Allows you to make oval and round table tops as well as mirrors, picture frames and specialty moldings. Secures quickly and easily to your workpiece by placing four screws through the corner mounting holes or use the vacuum attachment with 500 lbs. of solid clamping pressure. System is designed to work with most popular routers with the pre-drilled universal base plate.

Woodworker routing a large circle with a trim router on the oval and circle cutter jig's vacuum base

Most of woodworking is square. We make squares in the form of cabinets, tables, doors, etc. That's why it is so appealing when we get to see some break in the square, be it a slight curve or angle all the way to circles and ellipses. Circles and ellipses often get passed over by beginning woodworkers because the jigs to make them seem complicated or they don't know what tool to use.That's where Infinity's Oval and Circle Cutting jig with vacuum base comes in. Our jig makes cutting circles, arcs, and ellipses a very easy process. Unlike some of the other jigs on the market, ours has an attachment that allows you to draw out your circle or ellipse so that you can see your layout in your stock and saw off the excess material. This makes your routing job much easier.

The Oval and Circle cutting jig is very easy to assemble and fits most standard router bases. Simply remove your router's base plate and replace it with the included universal base that has been pre-drilled to accept most routers on the market. Then attach the L-bracket to the top of the base (see pictures below). The extension arms attach to the pivot base when you go to cut your circles.

Shipping box for the Oval/Circle Cutter with Vacuum Base
Unboxed parts of the oval and circle cutter: vacuum pivot base, blue acrylic router plate, rods, bracket and hardware
L-bracket mounted on the acrylic router base plate attached to a Bosch router

For cutting a circle, simply find the center point of your workpiece and mark it. Then draw extension lines along the two axis. Measure from the center point of your radius or half the diameter. Now you can attach the pivot base to the bottom of your workpiece with screws or to the top of your workpiece by using either double-sided tape or the vacuum base attachment. I attached ours to the bottom of my workpiece.

Next, simply align the holes in the pivot base over the axis lines we drew earlier and use the attached small screws to secure the base down. If you would like, you can now use the pencil attachment to layout your circle. Simply insert one of the pivots into the pivot base and slide it into the center position and attach the two setscrews into the dimples in the pivot base. Insert the rod which holds the pencil attachment into the pivot and extend the rod until you reach your desired length. Tighten the pivot screw onto the rod and draw your layout circle.

Next, I like to jigsaw off my waste to make routing a little easier. Try to stay as close to your layout line as you can.

Extension rod and pencil on the vacuum pivot base marking a circle layout line on the workpiece

For routing out the circle, I like to use a 1/2" diameter spiral router bit. If the pivot base is secured to the bottom, use a spiral upcut router bit. If the pivot base is secured to the top, use a spiral downcut router bit. You can also use the compression spiral router bit as another option for when it's secured on either side or take lighter passes with a plunge point straight router bit.

Now attach the router base to the pivot rod. Once the pivot rod is attached, set your distance by placing the router bit edge on the layout line. Make sure to tightly secure the pivot screw and L-bracket to the pivot rod. Now simply plunge the bit into the workpiece and travel in a counterclockwise motion. You can do this in either small/light passes for a cleaner cut or if you have removed the excess material you can do it in a single pass. And we now have a circle.

Spiral router bit cutting the circle through the router's clear base plate
Routing an oval on an MDF panel with the oval and circle cutter jig and plunge router

Ellipses can be set up in almost the same way. Find your center point on your workpiece and extend out your extension lines. Now make marks on the extension lines denoting the long axis and the short axis of your ellipse. You have a minimal differential length of 3.5" and a maximum differential of 9". Place both pivots in the pivot base after securing the base down. Set your desired long axis first by setting the pencil to the long mark and securing the pivot that is 90 degrees to the arm. I actually drew out multiple ellipses to show that you can orient your directions depending on material and wood grain. Next, set your short axis to the other pivot. Draw your layout line and make sure that the pivots follow the path you want. If they do, then you are ready to saw out your waste and attach your router. et your router the same way. Simply set the bit to the long mark and secure the 90-degree pivot and then take it back to the short mark and set the other pivot.

The Infinity Oval and Circle cutting jig is a definite help when making ovals, arcs, and circles. Please watch the video below for more detailed instructions.

Trim router on the oval and circle cutting jig routing a large circle in a white panel

Choosing a Jig for Cutting Circles with a Router

Jig How it works Best for
Infinity Oval & Circle Cutter The router rides on arms that pivot around a base fixed at the center of the workpiece Large circles and ellipses (ovals) for tabletops, mirrors and signs
Jasper circle guides A plate attached to your router with precisely spaced pivot holes Fast, accurate, repeatable circles and holes, such as speaker cutouts and inlays
Milescraft router circle guide kit An adjustable arm with a pivot pin that mounts to most routers Affordable, general circle and arc cutting
Trammel set Trammel points on a beam for layout Drawing large circles and arcs before cutting

Want a step-by-step look at plate-style guides? Read How to Cut Perfect Circles Using Your Router with Jasper Circle Guides.

Tips for Clean Router-Cut Circles

  • Use an upcut spiral bit. It clears chips from the groove and leaves a cleaner edge than a straight bit.
  • Take several shallow passes, about 1/8" to 1/4" deep each, instead of one deep cut.
  • Rough-cut the waste first with a jigsaw or bandsaw, staying outside the line, so the router only trims a little.
  • Support the workpiece on a sacrificial board or foam so the circle doesn't drop or shift when the final pass cuts through. Leave a few tabs if needed and trim them afterward.
  • Mind the bit diameter. Measure the radius to the inside or outside edge of the bit, depending on whether you're keeping the disc or the hole.
  • Move counterclockwise around the pivot when cutting a disc, so the bit cuts into the wood rather than climbing.

Circle Cutting FAQ

What router bit is best for cutting circles?

A 1/4" or 1/2" upcut spiral bit gives the cleanest results and clears chips from the cut.

How do I cut a circle without a center hole?

Attach the pivot to the workpiece with double-sided tape or use a vacuum-base jig, which holds the pivot without a screw hole.

Can I cut an oval with a router?

Yes, with an ellipse jig like the Infinity Oval & Circle Cutter, which moves the router along two axes at once.

Shop all circle cutting jigs.

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