Abstract: A boring tool with a variable length extension formed by a standard piece of pipe, for particular use in drilling downwardly from a wall studding header and through a fire brake bracing member which extends between the wall studs below the header, to facilitate the installation of piping, electric conduits, and the like, wherein a standard piece of pipe is threadedly connected by a coupling member at one end to a first shank portion of a boring tool, and a coupling member at its opposite end to an axially aligned second shank adapted for connection with a driving instrumentality. The coupling member in a modified form is provided at its pipe connection end with internally stepped threaded portions for selective connection with the ends of pipes of different diameter.