A cylindrical lock set including an operating unit having a cylindrical housing containing a unitary retractor frame of nonmetallic, low-friction material supporting a unitary metallic retractor slide. A latch unit releasably connected to the operating unit includes a case supporting a latch bolt releasably connected to the retractor slide by a female tailpiece. Coengageable cam surfaces on the tailpiece and on a deadlocking member carried by the latch bolt positively drive the deadlocking member to a deadlocking position relative to the case if an attempt is made to forcibly depress the latch bolt as by insertion of a tool between the outer edge of an associated door and strike plate. The operating unit also includes a locking mechanism for locking a rollback against rotation relative to the housing.