A turbine rotor and blade assembly for a steam turbine, comprising: a rotor having a dovetail slot formed therein and a locking blade groove positioned within the dovetail slot; a plurality of buckets positioned about the rotor, each of the buckets including a blade and a dovetail configured to mate the conforming dovetail slot of the rotor; and a locking blade positioned about the rotor, the locking blade comprising a multi-piece configuration including: a base having a first planar side with a first side base screw thread formed therein and a second planar side with a second side base screw thread formed therein; a first side hook on a first side of the base and a second side hook on a second side of the base, the first and second side hooks (240, 250) having planar mating surfaces configured to mate with the first and second planar sides (210, 230) of the base, respectively; wherein the first side hook comprises a first flange and the second side hook comprises a second flange, the first and second flanges (260, 265) extending outwardly from outer surfaces of the side hooks (240, 250); wherein the locking blade groove in the rotor is sized to accommodate the first flange and the second flange of the base of the locking blade; and wherein the outer surfaces of the first and second side hooks (240, 250), including the outer surface of the fist and second flanges (260, 265), are curved to mate with curved inner surfaces of the rotor, including inner surfaces of the locking blade groove in the rotor; and first and second side screws (280, 290) inserted into the screw threads formed in between the first or second planar side (210, 230) of the base and the planar mating surface of the first and second side hook (240, 250), respectively, to attach the first side hook and the second side hook to the base. a rotor having a dovetail slot formed therein and a locking blade groove positioned within the dovetail slot; a plurality of buckets positioned about the rotor, each of the buckets including a blade and a dovetail configured to mate the conforming dovetail slot of the rotor; and a locking blade positioned about the rotor, the locking blade comprising a multi-piece configuration including: a base having a first planar side with a first side base screw thread formed therein and a second planar side with a second side base screw thread formed therein; a first side hook on a first side of the base and a second side hook on a second side of the base, the first and second side hooks (240, 250) having planar mating surfaces configured to mate with the first and second planar sides (210, 230) of the base, respectively; wherein the first side hook comprises a first flange and the second side hook comprises a second flange, the first and second flanges (260, 265) extending outwardly from outer surfaces of the side hooks (240, 250); wherein the locking blade groove in the rotor is sized to accommodate the first flange and the second flange of the base of the locking blade; and wherein the outer surfaces of the first and second side hooks (240, 250), including the outer surface of the fist and second flanges (260, 265), are curved to mate with curved inner surfaces of the rotor, including inner surfaces of the locking blade groove in the rotor; and first and second side screws (280, 290) inserted into the screw threads formed in between the first or second planar side (210, 230) of the base and the planar mating surface of the first and second side hook (240, 250), respectively, to attach the first side hook and the second side hook to the base. a base having a first planar side with a first side base screw thread formed therein and a second planar side with a second side base screw thread formed therein; a first side hook on a first side of the base and a second side hook on a second side of the base, the first and second side hooks (240, 250) having planar mating surfaces configured to mate with the first and second planar sides (210, 230) of the base, respectively; wherein the first side hook comprises a first flange and the second side hook comprises a second flange, the first and second flanges (260, 265) extending outwardly from outer surfaces of the side hooks (240, 250); wherein the locking blade groove in the rotor is sized to accommodate the first flange and the second flange of the base of the locking blade; and wherein the outer surfaces of the first and second side hooks (240, 250), including the outer surface of the fist and second flanges (260, 265), are curved to mate with curved inner surfaces of the rotor, including inner surfaces of the locking blade groove in the rotor; and first and second side screws (280, 290) inserted into the screw threads formed in between the first or second planar side (210, 230) of the base and the planar mating surface of the first and second side hook (240, 250), respectively, to attach the first side hook and the second side hook to the base.