SPIRAL FLUTED TAP, TAPPING METHOD USING ITS SPIRAL FLUTED TAP, AND TAPPING MACHINE

摘要

PURPOSE: To increase surface finish on a side where the axial rake angle of a cutting edge is negative, and cut a female screw of desired dimensions accurately regardless of the type of material of a work. ;CONSTITUTION: An auxiliary cutting edge 30 is located at a heel section of a following flank 28 which is connected continuously to a cutting edge 24b on a side where an axial rake angle of a main cutting edge 24 becomes negative. On the other hand, when a tap is led forcibly for tapping, the phase of the tap is shifted between the start and end of feeding, and the flank of a female screw which is cut by the cutting edge 24b in the start of feeding is finish-cut by the auxiliary cutting edge 30 in the end of feeding. Thus the amount of phase shift is adjusted properly with the material, etc., of the work taken into consideration so that a female screw of desired effective diameter can be obtained.;COPYRIGHT: (C)1994,JPO&Japio