Abstract: A self-contained sheet metal cutter is mounted on a wheeled dolly and includes upper and lower power driven shear cutting wheels between which is engaged the plate or sheet to be cut. An adjustable trammel assembly extends from the dolly and includes a center point member engageable with an aperture in the plate to be cut and which corresponds to the center of the arc or circle. The trammel is adjustable to the radius of the arc or circle and the center point is engaged with the aperture in the sheet whereupon the wheeled dolly is pushed manually around the arc or circle as the shear wheels cut the sheet to the preset radius arc or circle. The rear wheel of the dolly is castor so that it follows the track readily and easily.