Threaded Bit Body Shank Connection for Rotary Drill Bits

The patent replaces the welding process (thermal/chemical joining) with a mechanical threaded connection system. The bit body includes an internally threaded bore that receives a threaded rod or stud, creating a mechanical interlock that avoids heat-affected zones entirely. This mechanical substitution resolves the contradiction by providing sufficient connection strength through thread engagement while preserving bit body material integrity.

The patent introduces a threaded rod or stud as an intermediary component between the bit body and shank. This intermediary element provides the connection function without requiring direct welding of the bit body to the shank, thereby avoiding the harmful thermal effects on the carbide material while still achieving strong mechanical attachment.

The patent eliminates the welding process entirely by implementing a mechanical threaded connection system. The internally threaded bore in the bit body engages with an externally threaded rod or stud, providing secure attachment through mechanical interlock. This approach resolves the harmful effects of heat-affected zones by substituting thermal joining with cold mechanical fastening, preventing crack formation while maintaining attachment strength.

The patent extracts the welding operation from the attachment process and replaces it with a mechanical fastening system. By removing the welding step entirely, the harmful thermal effects and associated crack formation are eliminated, while the mechanical threaded connection provides the necessary attachment strength without the detrimental heat-affected zone.