Drill bit
AssigneeBlack & Decker Inc.
InventorsAland SANTAMARINA, Glen V. STEINBRUNNER, David N. JOHNSON
Life of this patent
Estimating the term…
Abstract
An elongated drill bit has a shank at one end and working end at the other. A flute portion is between the working end and the shank. The flute portion is continuous with the shank and working end and is generally unitarily formed with them. The flute portion has at least one flute with a helix angle between approximately 30° and 35°. The working end has a pilot tip with a cutting portion. A tapered web is formed in the flute portion, a thickness of the web at the tip of the working end is about 9% to 15% of the nominal diameter.
Claims20
An elongated drill bit with a longitudinal axis comprising:
- a shank at a first tend having a nominal diameter;
- a working end at a second end;
- a flute portion between the shank and the working end, with the shank, the working end and the flute portion continuous with one another, the flute portion including at least one flute at a helix angle of approximately 30° to 35°, the working end comprises a pilot tip with a first cutting portion and a second cutting portion axially spaced from the first cutting portion, at a terminus of the flute portion, and including a pair of cutting edges on opposing sides of the pilot tip;
- and
- a tapered web formed in the flute portion, where a thickness of the web at the tip of the working end is approximately 9% to 15% of the nominal diameter.
A set of drill bits comprising:
- a first drill bit having a first nominal diameter, a second drill bit having a second nominal diameter, and a third drill bit having a third nominal diameter, each of the drill bits having a shank at a first end, a working end at a second end, and a flute portion between the shank and working end, where the shank, the flute portion, and the working end are continuous with one another, and the flute portion has at least one flute with a helix angle of approximately 30° to 35° and a tapered web, wherein the first drill bit has a nominal diameter of 17/64 inch or less and a thickness of the web at the working end of approximately 13% to 15% of the nominal diameter,
- wherein the second drill bit has a nominal diameter between 17/64 inch and 21/64 inch and a thickness of the web at the working end of approximately 11% to 13% of the nominal diameter, and
- wherein the third drill bit has a nominal diameter greater than or equal to 11/32 inch and a thickness of the web at the working end of approximately 9% to 10% of the nominal diameter.
Dependencies are inferred from the claim text.