The present invention relates to a straight edge device for use in conjunction with power tools such as radial saws, or table saws. The present invention is used for cutting an uneven edge of a board. The straight edge device includes a one piece board having a protuberance projecting from its lower surface that engages a groove of the table saw. The board is placed on the upper surface of the one piece board with the uneven edge hanging over the edges of the one piece board. As the straight edge device is pushed or pulled through the groove of the table saw, the cutting blade straights the uneven edge of the board.