Miniature internal boring tool

A miniature internal boring tool comprising:

• a shank portion;
• a cutting portion extending from the shank portion;
• and
• a central axis extending through the center of the shank portion and cutting portion;
• the central axis defining:
• a cutting direction;
• a forward direction from the shank portion towards the cutting portion;
• a rearward direction opposite to the forward direction;
• an outward direction extending perpendicular to, and outward from, the central axis;
• and
• an inward direction opposite to the outward direction;
• the shank portion comprising:
• a rear end;
• and
• a peripheral shank surface extending from the rear end to the cutting portion;
• the peripheral shank surface comprising:
• two to four shank flat surfaces;
• and
• two to four shank curved surfaces;
• the shank flat surfaces and the shank curved surfaces alternating about the central axis;
• the cutting portion comprising:
• a neck portion extending from the shank portion to the cutting portion;
• a gashed portion extending forward from the neck portion;
• a front end;
• and
• an imaginary plane perpendicular to the central axis and located at the front end;
• the gashed portion comprising:
• two to four integrally formed and angularly spaced apart teeth extending further in the outward direction than the neck portion;
• and
• a plurality of gashes;
• each tooth comprising:
• a rake surface;
• a relief surface;
• a cutting edge extending along an intersection of the rake surface and relief surface;
• and
• the relief surface comprising:
• a forwardmost relief sub-surface;
• and
• a rearwardmost relief sub-surface;
• the cutting edge comprising:
• a forwardmost cutting sub-edge extending along the intersection of the rake surface and forwardmost relief sub-surface;
• a rearwardmost cutting sub-edge extending along the intersection of the rake surface and rearwardmost relief sub-surface;
• and
• a nose cutting sub-edge connecting the forwardmost cutting sub-edge and the rearwardmost cutting sub-edge;
• a transition corner is formed between the rake surface of at least one of the teeth and the relief surface of the adjacent tooth to said at least one of the teeth, said adjacent tooth being located further in the cutting direction from said rake surface;
• wherein:
• outermost points of the cutting edges in the outer direction define an outer cutting diameter (OD) fulfilling the condition:
• 2 mm<OD<9 mm.