Damage resistant drill
AssigneeGeneral Electric Company
InventorsApostolos Pavlos Karafillis, Steven Robert Hayashi
Life of this patent
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Abstract
A drill according to an exemplary embodiment of the invention comprises a shank from which the drill is driven; a body connected to the shank, the body having a surface; a flute in the body; a cutting edge at a drill point; and a peripheral relief surface which extends outwardly from the surface of the body to an outer circumference of the drill, wherein the peripheral relief surface, for a cross section of the drill perpendicular to a drill axis, intersects the outer circumference at a peripheral point at an edge of the flute. The drill has an improved capacity to withstand a loss of coolant during drilling without severe overheating of the drill or workpiece and with little damage to the drill and workpiece.
Claims18
A drill comprising:
- a shank from which the drill is driven;
- a body connected to the shank, the body having a cylindrical surface;
- a flute in the body;
- a cutting edge at a drill point;
- and
- a peripheral relief surface which extends outwardly from the cylindrical surface of the body to an outer circumference of the drill, wherein the peripheral relief surface, for a cross section of the drill perpendicular to a drill axis, intersects the outer circumference at a peripheral point at an edge of the flute, wherein the peripheral point occupies a non-zero arc length on the outer circumference, the arc length being less than about 1.8 degrees.
A heat resistant drill comprising:
- a body having a cylindrical surface defined by a first radius;
- a flute formed helically in the body;
- a cutting edge formed at a drill point;
- and
- a peripheral relief surface, extending outwardly from the cylindrical surface of the body to an outer circumference defined by a second radius, wherein the peripheral relief surface meets the outer circumference along a helical line, and the helical line has a width which occupies a non-zero arc length on the outer circumference, the arc length being less than about 1.8 degrees.
A method of drilling comprising the steps of:
- rotating a drill point having a cutting edge;
- and
- reducing friction between the drill and a drilled hole by forming a relief angle between a tangent to an outer circumference of the drill and a peripheral relief surface of the drill, which peripheral relief surface extends from a cylindrical surface of a body of the drill and intersects the outer circumference of the drill at a peripheral point at an edge of a flute of the drill, wherein the peripheral point occupies a non-zero arc length on the outer circumference, the arc length being less than about 1.8 degrees.
Dependencies are inferred from the claim text.