Spade drill bits
AssigneeBlack & Decker Inc.
InventorsPaulo Sergio Dos Santos PELENTIR, Ricardo Casagranda DENDENA
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Abstract
A spade drill bit includes a shank extending along an axis from a rear end to a front end, the rear end configured to be coupled to a tool holder of a power tool, a blade including a paddle extending along the axis with a front portion and rear portion coupled to the front end of the shank, and a tip coupled to the front portion of the paddle. First and second primary cutting edges are disposed on a front edge of the front portion of the paddle and extend radially outward from the tip. At least the rear portion of the paddle is composed of a first steel alloy. The primary cutting edges are composed of a second steel alloy that has a greater hardness than the first steel alloy.
Claims22
A spade drill bit comprising:
- a shank extending along an axis from a rear end to a front end, the rear end configured to be coupled to a tool holder of a power tool;
- a blade including a paddle extending along the axis with a front portion and rear portion coupled to the front end of the shank;
- a tip coupled to the front portion of the paddle and extending along the axis;
- and
- first and second primary cutting edges disposed on a front edge of the front portion of the paddle and extending radially outward from the tip,
- wherein the paddle includes a first face with a first concave surface and a first convex surface on opposite sides of the axis, and a second face opposite the first face with a second concave surface and a second convex surface on opposite sides of the axis, the first concave surface opposite the first convex surface and the second concave surface opposite the second convex surface,
- wherein the rear portion of the paddle is composed of a first steel alloy, and
- wherein the front portion of the paddle is composed of a second steel alloy that has a greater hardness than the first steel alloy.
A spade drill bit comprising:
- a shank extending along an axis from a rear end to a front end, the rear end configured to be coupled to a tool holder of a power tool;
- a blade including a paddle extending along the axis with a front portion and rear portion coupled to the front end of the shank;
- a tip coupled to the front portion of the paddle and extending along the axis;
- first and second primary cutting edges disposed on a front edge of the front portion of the paddle and extending radially outward from the tip;
- and
- first and second secondary cutting disposed on chamfered corner edges of the front portion of the paddle and tapering radially outward from the primary cutting edges and axially rearward toward the rear portion,
- wherein at least the rear portion of the paddle is composed of a first steel alloy, and
- wherein the primary and secondary cutting edges are composed of a second steel alloy that has a greater hardness than the first steel alloy.
A spade drill bit comprising:
- a shank extending along an axis from a rear end to a front end, the rear end configured to be coupled to a tool holder of a power tool;
- a blade including a paddle extending along the axis with a rear portion coupled to the front end of the shank and a front portion coupled to a front end of the rear portion at a joint;
- an at least partially threaded frustoconical tip coupled to the front portion of the paddle;
- first and second primary cutting edges disposed on a front edge of the front portion of the paddle and extending radially outward from the tip;
- and
- first and second secondary cutting disposed on chamfered corner edges of the front portion of the paddle and tapering radially outward from the primary cutting edges and axially rearward toward the rear portion;
- wherein the paddle includes a first face with a first concave surface disposed on a first side of the axis and extending rearward from the first primary cutting edge along at least a portion of the paddle, and a second face opposite the first face with a second concave surface disposed on a second side of the axis opposite the first side and extending rearward from the second primary cutting edge axis along at least a portion of the paddle, and
- wherein the rear portion of the paddle is composed of a first carbon steel or low alloy carbon steel, and the front portion of the paddle, which includes the primary and secondary cutting edges, is composed of a second high chromium steel alloy or a high speed steel or tool steel alloy that has a greater hardness than the first steel alloy.
Dependencies are inferred from the claim text.