US PATENT SUBCLASS 175 / 385
.~ Bit with leading portion (e.g., pilot) forming smaller diameter initial bore

Current as of: June, 1999
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175 /   HD   BORING OR PENETRATING THE EARTH

327  DF  BIT OR BIT ELEMENT {21}
385.~ Bit with leading portion (e.g., pilot) forming smaller diameter initial bore {6}
386  DF  .~.~> Leading portion is separable starter
387  DF  .~.~> Leading portion is core forming type
388  DF  .~.~> Leading portion is a screw
389  DF  .~.~> Impact type {1}
391  DF  .~.~> Plural larger diameter steps
392  DF  .~.~> Leading portion is forked rotary type

DEFINITION

Classification: 175/385

(under subclass 327) Apparatus in which the bit is provided with a leading or pilot cutting edge or portion which forms a first bore of definable diameter, and a trailing cutting edge which increases the diameter of the first bore so that the boring outline of the bit will describe at least one peripheral axial step.

SEE OR SEARCH THIS CLASS, SUBCLASS:

334+, for rolling cutter bits with a leading cutter forming a smaller diameter initial bore.

SEE OR SEARCH CLASS

408, Cutting by Use of Rotating Axially Moving Tool,

195, 196, 211, 212, 215+, and 223+ for a cutting tool of that class type having a leading pilot or cutting edge.