A featherboard is used to keep smaller pieces of stock (board) pressed firmly against your table saw or router's fence. The design of a featherboard allows the stock to pass in one direction and causes resistance if moved in the other direction. This is useful for preventing kickback. A featherboard is basically a board with an angled end and 1/8 - 1/4 inch "fingers" cut into the beveled end. As stock is forced between the fence and the featherboard these fingers move slightly to allow the stock to pass. The firm squeeze helps keep the stock tight against the fence and help ensure a more accurate cut. In addition to keeping your stock against the fence, the fingers help reduce the chance of kickback. For more advanced work, such as with a router table, a second featherboard can be clamped to the fence to hold the stock down.
First Things First
The first thing you want to do is select a good board, preferably 3/4" plywood. It should be approximately 18"x5"x3/4". Cut a 30-45 degree miter at one end of the board.
Step 1 - Draw it
Draw a "stop line" approximately 3-5 down from the top of the bevel at the same angle as your miter cut.
Step 2 - Cut it
Place the long end of the miter against your table saw's fence and make a cut down to the stop line. The first cut should be approximately 1/4" from the edge. Turn off your table saw and adjust you fence 3/8" further away from the fence and make another cut. Continue in this fashion, adjusting each cut, until you reach the end.
Note: It is important for safety reasons that you start cutting on the long side of the bevel. If you start cutting along the short side you will quickly find that the later cuts do not have enough support. This can cause kickback.
Step 3 - Use it
To use your featherboard, place the stock you wish to cut against the fence. Position the featherboard firmly against it and clamp to the table. The feather board should be placed firm enough to keep the stock against the fence but should not make it difficult to push the stock into the cutter. It should be positioned between you and the blade. Positioning the featherbard further out may result in a kickback.
Note: Always use a push stick when working close to a cutter.