# How to Cut an Octagon on a Table Saw

A mathematical formula and a jig can help create a perfect octagon. Use these steps to make a jig that guides a table saw to rip off the corners of a square piece of wood.

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• Time

1 hour

• Price Range

\$1 - \$50

• Difficulty

Easy to Moderate

### Step 1: Make the Jig

To make the jig, cut one end of two 5" x 1" x 1" strips of hardwood at a 45-degree angle. Screw the strips of hardwood onto a 10" x 5" x 1" piece of plywood so they form a 90-degree angle (Image 1). Use a framing square to measure the angle, making sure it is exactly 90 degrees (Image 2).

### Step 2: Cut a Perfect Square

Determine the desired length of the finished octagon (O). Cut the work piece in the shape of a perfect square, with the length of its sides (S) determined by the following formula: S = 2.414 x O. Cut the square S inches on each side.

### Step 3: Set the Rip Fence

Calculate the rip distance (R) from the formula R = 2.914 x O. Set the rip fence at distance R. Place the jig against the rip fence so that the point where the two strips meet is against the fence.

### Step 4: Use the Jig

To use the jig, align one corner of the square work piece with the 90-degree angle on the jig (Image 1). Hold the work piece on top of the jig as you send it through the table-saw blade (Image 2). Repeat step 4 to cut off the remaining three corners of the work piece.

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