Out of the special that BO Machine Tools has manufactured for the superfinishing of crankshaft main journals and crankpins, the SFN 3 is undoubtedly the cheapest and the simplest solution. Featured by its extremely low weight and by its high maneuverability, the SFN 3 consists of a light frame fitted with a single-phase motor which drives an abrasive belt; the belt is guided by round pulleys; one of these, adjustable on its support, allows both the replacement and tension adjustment of the abrasive belt. The superfinisher is used with the crankshaft mounted in the machine; the operator guides the belt to the proper working positionand adjusts its pressure against surface of the crankshaft journal, thus removing quickly the minor surface faults left by the grinding operation, without altering the shape of the journals. This will greatly improve the pefformance features of the machined surfaces, for example more bearing capacity, lower friction coefficient, longer life. The SFN 3 superfinisher is normally supplied with singlephase electric motor for 220 V 50/60 Hz electrics.
