Power boring bits

  • US 4,050,841 A
  • Filed: 03/15/1976
  • Issued: 09/27/1977
  • Est. Priority Date: 03/15/1976
  • Status: Expired due to Term
First Claim
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1. A power boring bit comprising:

  • a. a shaft member having an elongated shank portion and a pointed tip portion at one end thereof configured to provide cutting surfaces along a segment of its axial length extending from the point of said tip portion, said cutting surfaces circumscribing a circle of rotation of maximum radius at a location along the length of said tip portion spaced from said point thereof, said tip portion having a generally axially extending planar shoulder portion spaced from said point with the radial distance to said shoulder portion being less than said maximum radius, said shoulder portion having a length dimension extending axially of said shaft member and a width dimension extending perpendicularly to said length dimension;

    b. a cutter disc having a planar body portion and a centrally disposed aperture therethrough receiving and extending about said tip portion at said axial shoulder portion, said cutter disc having a channel therein extending from the circumference thereof to said centrally disposed aperture therethrough, one edge portion bounding said channel extending at an angle from said plane of said body portion of the disc toward said point of said tip portion to provide a cutting lip portion with a root end adjacent said body portion of said disc and a free end spaced therefrom towards said point, said free end of said cutting lip portion having a cutting edge extending from the periphery of said disc to closely adjacent said axial shoulder portion of said tip portion intermediate the width of said axial shoulder portion and inwardly of the circle of rotation of maximum radius; and

    c. means bonding said disc to said tip portion.

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