Indexable drill assembly with coolant system

An indexable drill assembly (10), comprising:

• a drill body (12) having a central longitudinal rotational axis (CL), the drill body (12) comprising a shank portion (14) and a fluted cutting portion (16), the fluted cutting portion (16) having a front clearance face (20) and a plurality of flutes (22), the fluted cutting portion (16) includes a central insert pocket (24) proximate the front clearance face (20) and a central cutting insert (100) received in the central insert pocket (24), the central cutting insert (100) having an active cutting edge defining a cutting length (CL1) in a lateral direction extending radially from the central longitudinal rotational axis (CL), the fluted cutting portion (16) also including a peripheral insert pocket (26) proximate the front clearance face (20) and a peripheral cutting insert (200) received in the peripheral insert pocket (26), the peripheral cutting insert (200) having an active cutting edge defining a cutting length (CL2) in a lateral direction extending radially from the central longitudinal rotational axis (CL);
• and
• a coolant system (30) comprising a plurality of primary coolant channels (32) extending entirely through the shank portion (14) and at least partially into the fluted cutting portion (16) of the drill body (12), and one or more secondary flute coolant channels (34) extending from one of the plurality of primary coolant channels (32) and terminating at a flute coolant exit aperture (36) formed in one of the plurality of flutes (22),
• wherein the flute coolant exit aperture (36) produces a projection (40) of coolant having a central, longitudinal axis (42) that intersects one of the following:
• 1) a first vertical plane (PA1) defined by a two-dimensional surface having an area (A1) defined by the following equation:
• A1=(CL1*0.85)*((CL1/√{square root over (2)})+1.2 mm)
• where,
• CL1 is the cutting length of the central cutting insert (100) in the lateral direction;
• 2) a first horizontal plane (PB1) defined by a two-dimensional surface having an area (A2) defined by the following equation:
• A2=(CL1*0.85)*(IC1/2)
• where,
• CL1 is the cutting length of the central cutting insert (100) in the lateral direction, and
• IC1 is a diameter of an inscribed circle (IC) of the central cutting insert (100);
• 3) a second vertical plane (PA2) defined by a two-dimensional surface having an area (A3) defined by the following equation:
• A3=(CL2*0.85)*((CL2*0.6)+0.5 mm)),
• where,
• CL2 is the cutting length of the peripheral cutting insert (200) in the lateral direction;
• and
• 4) a second horizontal plane (PB2) defined by a two-dimensional surface having an area (A4) defined by the following equation:
• A4=(CL2*0.85)*(IC2/2)
• where,
• CL2 is the cutting length of the peripheral cutting insert (200) in the lateral direction, and
• IC2 is a diameter of an inscribed circle (IC) of the peripheral cutting insert (200).