Abstract: A circular saw has adjustable blades mounted on a splined blade arbor. A guide engages a portion of each blade spaced from the blade arbor so as to facilitate movement of the blade along the blade arbor without tilting or canting. The guides are mounted on a guide arbor. Each blade and associated guide are connected to an actuator by shifter bars which are slideably disposed in the splines. The actuator comprises a connecting plate, each connecting plate being provided with a shifting cylinder for effecting movement of the mounting plate and associated simultaneous displacement of an equal amount by the blade and guide associated with it. Preferably three round shifter bars disposed in half-round splines circumferentially spaced 120.degree. from each other are associated with each blade and guide. The mounting plates are disposed on shafts having gear wheels at their opposite end cooperating with racks.