How to Build a Circle Cutting Bandsaw Jig

Measure the length and width of the table of the bandsaw. Add 8 inches to the length dimension and 4 to the width. Cut a section out of a plywood board with dimensions equal to those of the measurements and additions with a circular saw. Mark the board "A" with a pencil. Cut a second board equal to the first, but add another 1/12 of an inch to the width. Mark it board "B."

Snap a chalk line down the lengthwise center-line of board A. Parallel to and 3/8 of an inch on each side of the center-line, snap two more chalk lines. Lay the blade of the circular saw on a 45-degree angle. With the bottom of the blade angled away from the board's center-line, cut through the board along both outside chalk lines. The result is a strip of board that is tapered on two sides and has a broad side and a narrow side. In addition, the cut creates two large boards with one tapered edge apiece -- boards 1 and 2.

Place the tapered strip of wood -- the broad side down -- on the lengthwise center-line of board B. Place boards 1 and 2 on board B, one on each side of the strip. Fit them together like a jigsaw puzzle resembling the uncut board below. Slide boards 1 and 2 to the outside edges of board B. This leaves 1/5 inch between the strip and boards 1 and 2 allowing it to slide back and forth. Screw boards 1 and 2 to board B, along the outside edges, one screw every 9 inches.

Drill a screw into the narrow edge of the wood strip, 3 inches from one end, 1 inch deep. Cut off the top 1/2 inch of the deck screw with a grinder. Drill a 1/4 inch hole in the center the piece of wood you wish to cut in a circle and place it on the jig's slide screw. Start the bandsaw, begin cutting as you rotate the wood around the jig's screw.