Abstract: The reduction gear box for a chain binder generally includes a housing member, a nozzle on the housing member to which a power tool may be connected, and an opening in the housing member within which the shaft portion of a chain binder may extend. The housing member includes a worm gear assembly and a main gear assembly therein. The worm gear assembly is in communication with the main gear assembly such that rotation of the worm gear assembly causes the main gear assembly also to rotate. In use, a shaft portion of a chain binder can be positioned within the housing opening and in communication with the main gear assembly. The power tool can be operated to rotate the worm gear assembly, and thereby effectuate rotation of the main gear assembly to extend or retract the chain binder in communication therewith.