Boring bit
First Claim
Patent Images
1. A drill bit comprising:
- a shank formed along a first end of said drill bit;
a cutting part formed along a second end of said drill bit opposite said first end;
a central longitudinal axis through both said shank and said cutting part;
at least primary and secondary cutting edges designed so that said drill bit drills into a full material of a metallic work piece to make a drillhole, said at least primary and secondary cutting edges being arranged in a point-symmetric arrangement, said primary cutting edge being located at said second end of said drill bit, said secondary cutting edge being located along a substantial axial length of said cutting part, and said at least primary and secondary cutting edges are inclined relative to said central longitudinal axis of said drill bit;
a flute formed along a substantial axial length of said cutting part;
an axial rake angle formed by helically disposing said flute, said secondary cutting edge being inclined in a cutting direction over a substantial axial effective length to thereby form a negative axial rake angle such that dynamic forces acting on said primary cutting edge apply tension to said drill bit, said axial rake angle ranging from between −
1°
to −
10°
.
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Accused Products
Abstract
A boring bit, especially a multi-blade boring bit. The bit preferably has a point symmetric cutting edge arrangement having main and secondary cutting edges that are tilted towards the axis of the boring bit. In order to stabilize the tool against vibrations cased by the cutting force, the secondary cutting edge is tilted along an effective length that is substantially axial in the direction of cutting thereby having a negative tool side rake.
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Citations
18 Claims
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1. A drill bit comprising:
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a shank formed along a first end of said drill bit;
a cutting part formed along a second end of said drill bit opposite said first end;
a central longitudinal axis through both said shank and said cutting part;
at least primary and secondary cutting edges designed so that said drill bit drills into a full material of a metallic work piece to make a drillhole, said at least primary and secondary cutting edges being arranged in a point-symmetric arrangement, said primary cutting edge being located at said second end of said drill bit, said secondary cutting edge being located along a substantial axial length of said cutting part, and said at least primary and secondary cutting edges are inclined relative to said central longitudinal axis of said drill bit;
a flute formed along a substantial axial length of said cutting part;
an axial rake angle formed by helically disposing said flute, said secondary cutting edge being inclined in a cutting direction over a substantial axial effective length to thereby form a negative axial rake angle such that dynamic forces acting on said primary cutting edge apply tension to said drill bit, said axial rake angle ranging from between −
1°
to −
10°
.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification