How to Rout a Perfect Circle in Wood With a Simple Shop-Made Jig

Cutting a straight line with a circular saw is easy. Cutting a true circle is a different problem entirely. A jigsaw wanders, a bandsaw needs a steady freehand line, and neither one guarantees the same radius all the way around. The fix doesn’t require a new tool. It just requires turning the router into a compass.

Complete circular groove routed into a wood panel on a workbench, with the router set to the side — One full pass with the pivot jig leaves a crisp, perfectly round groove. No jigsaw or bandsaw required.

This is the shop-made pivot jig used to cut a clean circle straight through a wood panel, photographed start to finish in a home garage shop. It’s a simple setup: a router bolted to a board, a fixed pivot point, and a series of passes that get deeper each time. No specialty circle-cutting jig, no compass saw attachment. Just a router and a scrap of wood.

The Technique: Why a Shop-Made Circle Jig Beats a Jigsaw

A router circle jig (also called a trammel jig or pivot-arm jig) works on the same principle as a school compass. One end of an arm is fixed to a center point; the other end holds the cutting tool. Swing the arm and the router traces a perfect arc every time, because the radius never changes. That consistency is the whole advantage over a freehand cut: every point on the circle ends up exactly the same distance from center, which matters if the piece needs to sit flush in a round opening, spin true on a base, or simply look right to the eye.

It also means the cut can be sneaked up on. Instead of committing to one pass all the way through a panel with a jigsaw blade that can drift, the router takes several shallow passes at the same radius, cutting a groove that gets deeper each time until it finally breaks through.

Tools & Setup

The jig itself is built from what’s already lying around a shop: a compact router and a length of scrap board long enough to reach from the center point out to the edge of the circle.

Compact/trim router (a DeWalt trim router in this build)
A flat scrap board to serve as the pivot arm
Screws to mount the router’s base to the arm
F-style bar clamps to hold the panel and jig steady
A stable, flat workbench

Close-up of a wood sub-base block with a router bit protruding through a drilled center hole, mounted with four screws — The router’s factory base is swapped for this shop-made block, drilled and screwed on to create the fixed pivot point for the arm.

The core of the jig is this: the router’s stock base plate is removed, and a wood block is screwed on in its place. That block has a hole drilled through it so the bit still passes through cleanly, and it becomes the mounting point for the long pivot arm. Everything downstream depends on that connection being solid. Any play here shows up as an uneven radius in the finished circle.

Compact router mounted to a shop-made wood sub-base clamped to a workbench, set up as a circle-cutting pivot jig — The router is screwed to a wood sub-base that acts as the pivot arm for the circle jig.

The panel being cut here is clamped flat to a workbench so it can’t shift mid-pass. A stable, mobile shop cart like the one below made a convenient work surface for staging material before the panel moved into the garage for the actual routing.

Rolling wood workshop cart with open storage lid revealing wood cutoffs and drawers, sitting on a backyard patio — The mobile workbench cart doubles as a stable, wheel-around surface for jig-based routing work in the shop.

Backyard patio woodworking setup with a pop-up canopy tent, mobile workbench, and lumber staged for a build — The outdoor staging area where material for this project was set up before the circle-routing step moved into the garage.

Step by Step: Routing the Circle

Build the pivot jig by removing the router’s stock base and screwing on a wood sub-base with a hole for the bit, then attaching a long arm that reaches from that pivot point to the edge of the intended circle.
Mark the center of the circle on the panel and set the pivot end of the arm at that point.
Clamp the panel firmly to the workbench so it cannot shift while the router is swung around it.
Set the router to a shallow cutting depth for the first pass. Cutting all the way through in one pass isn’t the goal here.
Swing the router around the pivot in a steady, continuous motion, letting the arm’s fixed length set the radius.

Overhead view of a router cutting a circular groove into a wood panel, with sawdust building up around the cut line — The router follows the pivot arm around a fixed center point, scoring a clean circular groove into the panel.

Router and pivot-arm jig midway through cutting a circle into a wood panel, seen from a higher angle with clamps visible — Repeated passes gradually deepen the groove until the router cuts all the way through the panel.

Router and wood pivot-arm jig clamped to a cluttered workbench, viewed from a slightly different angle — A second look at the jig setup just before the pivot point is locked down and the cut begins.

Results: What You End Up With

The payoff is a groove that’s the same width and the same distance from center all the way around: a true circle, cut without a single freehand movement. Once the router has cut all the way through, the disc separates cleanly from the surrounding waste material.

Wood panel with a complete circular groove cut all the way around, router and cord set beside it on the workbench — The finished cut: a full circle scored into the panel, ready to be separated from the surrounding waste material.

Tips for a Clean Cut

Make several shallow passes rather than one deep one. It’s easier on the router, the bit, and the accuracy of the cut.
Clamp the panel down solidly. Any shift mid-pass shows up as a flat spot or step in the circle.
Keep the pivot connection tight. A loose screw at the pivot point is the most common way a “circle” ends up slightly egg-shaped.
Clear sawdust between passes so the existing groove stays visible as a guide for the next one.

When to Use This Technique

This same pivot-jig approach works for any project that needs a true circle cut in wood: a round tabletop, a lazy susan blank, a sign, a wheel, or a round insert that needs to fit a specific opening. The arm length is simply set to whatever radius the project calls for, and the same shallow-pass, swing-and-repeat process applies regardless of the final size.