DRILL TAP FOR FORMING MICRO DIAMETER SCREW TAP AND MANUFACTURING METHOD THEREOF

摘要

The present invention relates to a subminiature drill tap tool (2) which forms a screw hole to fasten a subminiature screw with a 1-2 mm outer diameter, and includes a drill tap main body (4) with an HRc 55-70 hardness made of high-speed steel material containing cobalt (Co). A drill blade unit (6) and a tap unit (8) are formed consecutively from the fore-end unit of the drill tap main body (4) in order to process a screw hole to fasten a subminiature screw with the 1-2 mm outer diameter. One or more groove-shaped chip discharge paths (10) are extended from the drill blade unit (6) and the tap unit (8) in order to discharge the chips. The internal angle (ω) of the drill blade unit (6) is between 115-125 degrees, and the helix angle of the chip discharge path (10) is between 5-30 degrees. Therefore, the subminiature drill tap tool (2) can form a very small screw hole with a 1-2 mm size without separately performing drilling and tapping work.