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Class Information
Number: 175/385
Name: Boring or penetrating the earth > Bit or bit element > Bit with leading portion (e.g., pilot) forming smaller diameter initial bore
Description: 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.
Sub-classes under this class:
Patents under this class:
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