Patent ID: 7441433

Claim:
A tool adapted to form a threaded hole in a hydroformed part while the part remains in a hydroforming die cavity, comprising; a hole-piercing end portion adapted on advancement of the tool to pierce and form a hole in the part while hydroforming fluid under pressure remains in the part; an extruding portion adapted on continued tool advancement to extrude an annular extrusion extending into the tube and having a cylindrical inner surface; a sealing portion directly adjacent the extruding portion and having a cylindrical surface having a tight fit with the cylindrical inner surface of the annular extrusion and thereby adapted on continued tool advancement to seal the hole during the ongoing advancement and extrusion of the annular extrusion so that hydroforming fluid remains under pressure without leakage and loss of pressure; and a thread-forming portion directly adjacent the sealing portion and having controlled root diameter tapping threads adapted upon simultaneous rotation and continued advancement to form an internal thread within the extruded annular extrusion, said formed internal thread having tightly controlled major diameter, thread flank and minor diameter to obtain tight contact of the thread-forming portion of the tool with the formed internal thread of the extrusion, whereby the to prevent the leakage and loss of pressure of the hydroforming fluid during the simultaneous rotation and continued advancement, and the subsequent rotation and extraction of the thread-forming potion of the tool from the hydroformed part.