Patent ID: 9737944
Date: 2017-08-22
CPC Classifications: B23G,Y10T

Claim:
1. A thread-cutting tap that is to be rotated in a rotation direction for cutting an internal thread in a work material, the thread cutting tap comprising: a thread portion having an external thread provided therein, and including a chamfered portion and a complete thread portion that is axially contiguous to the chamfered portion; a flute extending from an axially distal end of the tap toward an axially proximal end of the tap, the external thread having an end face defined by one of widthwise opposite end portions of the flute; a rake face defined by a radially inner portion of the end face of the external thread at the one of the widthwise opposite end portions of the flute, so as to extend along the flute; a cutting edge defined by a radially outer portion of the end face of the external thread at the one of the widthwise opposite edges of the flute, so as to be adjacent to the rake face and extend along the flute; and the cutting edge being provided with a protrusion portion at least in a radially outer end portion of the chamfered portion, such that the protrusion portion protrudes from the rake face forwardly in the rotation direction and extends along the cutting edge.