Miter box for a portable electric saw

A miter box for selectively facilitating 45.degree. and 90.degree. cuts in the end portions of a molding strip or the like by means of a portable electric saw of the type that has a slotted slide shoe through which the rotary blade of the saw extends, said miter box comprising an elongated open-ended body having a top wall for sliding reception of the slide shoe of the saw, a strip-supporting bottom wall, and front and rear vertical walls, the opposite ends of said body being bevelled on a 45.degree. bias so that the vertical planes thereof extend at a right angle to each other, means on said top wall establishing a pair of guide edges for the inside edge of the slide shoe of the saw, said guide edges extending parallel to said bevelled ends of the miter box body and spaced therefrom a distance substantially equal to the distance between the inside edge of the saw slide shoe and the saw blade whereby, when the saw shoe is drawn across said top wall with its inside edge in sliding engagement with one of said guide edges, a 45.degree. extrusion will be effected on the strip, an auxiliary guide piece separately formed from the miter box body, and cooperating locating means effective between said top wall and the auxiliary guide piece whereby the latter may be fixedly positioned on the former, said guide piece being provided with a guide edge which, when the guide piece is effectively located on said top wall, extends at a right angle to the longitudinal axis of the miter box body where, when the saw shoe is drawn across said top wall with its inside edge in sliding engagement with the guide edge on the guide piece, a 90.degree. extrusion will be effected on the strip.