Modular drill with diamond cutting edges

A modular drill for machining applications wherein the modular drill has a generally cylindrical body with peripheral walls about a central longitudinal axis and with an upper end, wherein the modular drill comprises:

• a. a centrally located pilot drill protruding from the upper end along the longitudinal axis,
• b. at least two cutting inserts, wherein each cutting insert has a top surface, a bottom surface and a plurality of sides therebetween with a cutting edge defined at the intersection of the top and side surfaces;
• wherein a cutting edge from each insert protrudes axially from the upper end of the body and is operative to engage a workpiece;
• c. wherein each operative cutting edge extends in a radial direction such that, when viewed along the central axis toward the upper end, the operative cutting edges combine to completely overlap the radial distance extending from the pilot drill to the peripheral walls, d. wherein the pilot drill is made of a non-diamond;
• and
• e. wherein the operative cutting edge of each of the cutting inserts has a full face polycrystalline diamond layer thereupon and the operative cutting edge of each insert is integral with this diamond layer;
• and
• f. wherein the rake surface of each insert has indicia to identify the cutting edges of the cutting insert.

A method of machining a titanium workpiece using a modular drill having a generally cylindrical body with peripheral walls about a central longitudinal axis and with an upper end, a centrally located pilot drill protruding from the upper end along the longitudinal axis, at least two cutting inserts, wherein each cutting insert has a top surface, a bottom surface and a plurality of sides therebetween with a cutting edge defined at the intersection of the top and side surfaces;

• wherein a cutting edge from each insert extends axially from the upper end of the body and is operative to engage a workpiece;
• wherein each operative cutting edge extends in a radial direction such that, when viewed along the central axis toward the upper end, the operative cutting edges combine to completely overlap the radial distance extending from the pilot drill to the peripheral walls, wherein the pilot drill is made of a non-diamond;
• and wherein the operative cutting edge of each of the cutting inserts has a diamond surface, the method comprising the steps of:
• a) positioning the modular drill adjacent to the titanium workpiece;
• and
• b) advancing the modular drill into the workpiece to the desired depth.

A method of machining a fiberglass workpiece using a modular drill having a generally cylindrical body with peripheral walls about a central longitudinal axis and with an upper end, a centrally located pilot drill protruding from the upper end along the longitudinal axis, at least two cutting inserts, wherein each cutting insert has a top surface, a bottom surface and a plurality of sides therebetween with a cutting edge defined at the intersection of the top and side surfaces;

• wherein a cutting edge from each insert extends axially from the upper end of the body and is operative to engage a workpiece;
• wherein each operative cutting edge extends in a radial direction such that, when viewed along the central axis toward the upper end, the operative cutting edges combine to completely overlap the radial distance extending from the pilot drill to the peripheral walls, wherein the pilot drill is made of a non-diamond;
• and wherein the operative cutting edge of each of the cutting inserts has a diamond surface, the method comprising the steps of:
• a) positioning the modular drill adjacent to the fiberglass workpiece;
• and
• b) advancing the modular drill into the workpiece to the desired depth.