Abstract: A guide plate of a chain saw is disclosed and the guide plate comprises: a rectangular metal plate, which is constructed by a body shaped as a guide plate and an eliminated portion elongated around the peripheral of the body; wherein the two surfaces of the front end of the body are elongated to a boundary surface of the eliminated portion individually and corresponding to two indentations of an arc portion toward front, two welded welding powder structures are inside the two indentations so as to let the top surface and the bottom surface of the metal plate be two flat surfaces, the body is separated from the eliminated portion, the welded welding powder structures are disposed at the front edge of the front end of the body, a guide groove is disposed in between the two welded welding powder structures and toward the body.

Abstract: A structure for casehardening a fixture of a guide plate of a chain saw is disclosed and comprises: a metal member being larger than the guide plate and having a slot, the dimension between the two edges of the slot being a sum of the dimension of the outer figure of the guide plate and the dimension of a tolerance, the tolerance being defined as an allowable electrode discharging distance; and at least one cooling structure being disposed around one of the edges utmostly and only having one inlet and one outlet, other useless opens being sealed by sealing structures.