Straight hole insert drill bit
A drill bit is disclosed for maintaining a desired direction of drilling or to reduce the deviation already established. The drill bit includes a plurality of legs with each leg having a cone cutter rotatively supported thereon. A plurality of annular rows of cutting inserts are circumferentially mounted on the conical surface of each cutter. Each cone cutter further includes a heel portion adjacent the base of the conical surface. The heel portion is of sufficient mass to support the gage row of cutting elements. The gage row of each cone extends further out from the cone axis than any of the intermediate adjacent rows in such a manner that the annular area of the hole bottom cut by the gage inserts is lower than any other area cut by the intermediate rows of cutting inserts. This extended gage row construction enables the gage inserts to cut into any sloping wall to produce a sharp corner and bring the hole back into line with the drill string. The cutting inserts of each gage row include relatively large cutting faces in the direction of the sidewalls of the bore hole in order to have substantial surface contact with the gage of the bore hole.
- Assignee:
- Smith International Inc
- Patent Number(s):
- US 4231438
- OSTI ID:
- 6506953
- Country of Publication:
- United States
- Language:
- English
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