Abstract: A drag-type drill bit for bore hole drilling in earth formation comprises a bit body having a threaded pin on one end for coupling to a drill string. A substantially dome-shaped cutter head is formed integral with the bit body opposite from the threaded pin. Formed integral with and extending from the cutter head is a plurality of circumferentially spaced fixed and/or variable pitch spiral blades having a succession of curved segments. The variable pitch pattern curves from substantially the center of and around the cutter head to the gage area. A plurality of generally cylindrical cutting elements, such as PDC elements, are fixed to each of the spiral blades and a plurality of nozzles are positioned around the cutter head to direct drilling fluid passing through the bit body against the blades to the annulus surrounding the bit body and the bore hole.

Abstract: A method for creating a rapid prototype mold for parts of an earth boring tool for manufacture thereof comprises initially optimizing the drill bit design and integrating this design into CAD code. The CAD code is utilized to generate a prototype file in a computer outputting command signals to a laser, and a laser scanner to prototype a mold utilizing stereolithography, selective laser sintering, or laminated object manufacturing, in addition to other prototype techniques to manufacture earth boring tool parts.