A Quick Guide to Cutting a Circle in Wood
The circle is one of the hardest shapes to cut cleanly in woodworking. A router on a simple circle jig cuts a near-perfect circle every time, when a quick cut with your jigsaw just won’t do. Here are the steps.
Unplug the router (or remove its battery) whenever you attach the jig or change the bit.
#1. Cut the jig blank. Use a strip of 1/4-inch plywood or hardboard as wide as the router’s base. Make it a few inches longer than the radius of the largest circle you plan to cut. Remove the router’s sub-base and trace it on one end of the strip.
#2. Drill the mounting holes. Using the sub-base as a template, mark and drill its screw holes in the jig. Countersink them so the screw heads sit below the surface. Drill a larger center hole for the bit.
#3. Attach the jig to the router. Screw the jig to the router base in place of the sub-base, using the original screw holes. You may need longer screws, depending on the jig’s thickness.
#4. Drill your pivot holes. Install a straight bit. Measure from the inside edge of the bit along the arm and mark the radius you need. Drill a small pivot hole there. You can drill a row of holes about 1 inch apart for common sizes.
#5. Set the pivot. Mark the center of the workpiece by drawing lines from corner to corner. Clamp the workpiece over scrap or foam so the bit won’t cut your bench. Drive a small nail through the pivot hole into the center mark, but not so tight that the jig can’t turn.
#6. Now cut your circle. Set the first pass shallow, about 1/8 inch. Start the router with the bit clear of the wood, plunge, and swing the router around the pivot. Lower the bit 1/8 to 1/4 inch per pass, as Family Handyman recommends, until you cut through. Several light passes give a cleaner edge than one deep cut and are safer.
Cutting a circle in wood takes a little preparation, but a simple jig makes it repeatable. Wear eye and hearing protection, keep the router moving so it doesn’t burn the wood, and make a test cut on scrap first. Find the best routers for woodwork to get started on your next project.
Sources
- How To Make a Router Circle Jig, Family Handyman
- How To Cut a Perfect Circle With a Router, This Old House
