Abstract: A spinning rotor for use in an open end spinning device for producing twisted yarns, the spinning rotor being symmetrical about a longitudinal axis and comprising a body machined from a unitary piece of self-lubricating plastic. The body includes a peripheral wall which defines an exterior surface which is cylindrical with respect to the longitudinal axis of the rotor. A reinforcing rim having the shape of a right circular cylinder and defining an internal cylindrical wall is positioned in abutment with the cylindrical exterior surface of the peripheral wall to reduce deformation of the body when the body is subjected to centrifugal forces.