What's shaped like a triangle with the points cut off, has sharp teeth all the way around the outside, and fits any 7 1/4-in. portable circular power saw?

It's the Crazy Blade which cuts backward as well as forward, straight lines or curves, dadoes, and other special shapes.

James Malarney of Gladstone Marketing, Oregon City, Ore., says the secret of the Crazy Blade is that the blade leaves the cut three times in each revolution. So, by moving the saw slowly, you can turn it while the blade is out of the material and make a variety of cuts which are impossible to do with conventional blades. The Crazy Blade works best in 1/4 to 1/2-in. plywood, and works well at depths to 1 1/2 in., but can cut thicknesses up to 1 3/4 in.

The Crazy Blade has a somewhat narrow range of applications, says Malarney, and is not recommended for general straight cutting. So, most cutting should still be done with a conventional blade, with the Crazy Blade reserved for making curves, and for cutting special shapes or patterns. Because of its shape, the Crazy Blade bucks or bounces against the wood more than conventional blades do. Therefore, Malarney recommends that operators hold the saw firmly against the work, and clamp wood down if possible, especially when cutting smaller pieces.

The Crazy Blade fits 5/8-in. arbors and can be resharpened.