NotchLoading plan…
Loading plan…
A circular saw cuts straight lines by design, which makes clean circles awkward without a guide. This jig solves that with one pivot hole and one fixed edge: pin the hole at your workpiece's center and swing the saw around it, and the fixed edge keeps the saw's base plate riding a consistent, trimmed-flush line the whole way around.
The pivot hole's position isn't arbitrary — it has to account for your specific saw's blade offset from the base plate edge, not just the radius you want. Trim the jig's overhang flush with your own saw before drilling anything, so the jig is calibrated to the tool you'll actually use it with.
Built once, this jig cuts any circle up to the length of plywood you used — no need to rebuild it for a different diameter.
| Item | Qty |
|---|---|
| 1/4" plywood, 12in x 48in | 1 each |
| Pine board, 1x2, 4 ft | 1 each |
| Wood screws, 1" | 8 each |
Overall cost: $. Lumber prices vary by region, species, and season, so we give a band rather than a figure we would only be pretending to know.
| Part | Qty | T × W × L |
|---|---|---|
| Jig base1/4" plywood | 1 | 1/4" × 12" × 48" |
| Guide rail1x2 | 1 | 3/4" × 1 1/2" × 48" |
Buy 2 boards at 8 ft.
1 board
1 board
Assumes 8 ft stock, a 1/8" saw kerf, and buying each part at its own width. Change the board size or kerf on the full board plan →
Cut a piece of 1/4" plywood about 12in wide and as long as your largest needed radius.
Attach the 1x2 guide rail to one edge of the base with glue and screws, leaving about a 1-1/2in overhang past the rail.
Trim the overhang flush using your circular saw's own base plate riding against the 1x2 as a guide — this calibrates the jig to your specific saw.
Find the plywood's width-wise center, measure out your desired radius along its length, and drill a pivot hole sized to account for your saw's blade offset from the base plate edge.
Pin the pivot hole at the center of your workpiece and swing the saw around it to cut the circle, clamping the jig down if it tends to rotate.
No reviews yet
Sign in to review this plan or share your build.
No reviews yet. Be the first to build this.