R-shaped angle knife for lathe

The utility model relates to a turning tool used for a lathe, in particular to an R-shaped angle knife. The R-shaped angle knife comprises a knife body and a knife edge, wherein the middle part of the knife body is cubic, symmetrical taper angle shanks are arranged at the both ends of the knife body, truncated cone shaped knife edges are respectively arranged on the taper angle shanks at the both ends of the knife body, and circular grooves are formed on cutting surfaces of the truncated cone shaped knife edges. Since the circular grooves are formed on the cutting surfaces of the truncated cone shaped knife edges, the purposes of comprehensive cutting and bidirectional feeding can be achieved, the tool changing is eliminated, the purpose of one knife with multiple functions is further achieved, and the R-shaped angle knife is more suitable for non-metal processing and groove type workpiece processing, saves both time and labor, and has high efficiency and high machining accuracy.