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Class Information
Number: 175/391
Name: Boring or penetrating the earth > Bit or bit element > Bit with leading portion (e.g., pilot) forming smaller diameter initial bore > Plural larger diameter steps
Description: Apparatus in which the cutting edges of the bit are arranged so that the boring outline of the bit will describe at least two peripheral axial steps.

Patents under this class:
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Patent Number Title Of Patent Date Issued
8499834 Milling tool for establishing openings in wellbore obstructions Aug. 6, 2013
8172010 Rotary drill bit steerable system and method May. 8, 2012
8074741 Methods, systems, and bottom hole assemblies including reamer with varying effective back rake Dec. 13, 2011
7971645 Four mill bottom hole assembly Jul. 5, 2011
7958953 Drilling tool Jun. 14, 2011
7896106 Rotary drag bits having a pilot cutter configuraton and method to pre-fracture subterranean formations therewith Mar. 1, 2011
7887263 Ground anchor Feb. 15, 2011
7882907 Earth boring bit Feb. 8, 2011
7384223 Anchoring drill bit, system and method of anchoring Jun. 10, 2008
7293617 Polycrystaline diamond compact insert reaming tool Nov. 13, 2007
7137463 Polycrystaline diamond compact insert reaming tool Nov. 21, 2006
7048078 Expandable underreamer/stabilizer May. 23, 2006
6926099 Drill out bi-center bit and method for using same Aug. 9, 2005
6902014 Roller cone bi-center bit Jun. 7, 2005
6860344 Monolithic roof cutting bit insert Mar. 1, 2005
6840337 Method and apparatus for removing cuttings Jan. 11, 2005
6824331 Screw form anchor device Nov. 30, 2004
6742607 Fixed blade fixed cutter hole opener Jun. 1, 2004
6695080 Reaming apparatus and method with enhanced structural protection Feb. 24, 2004
6659207 Bi-centered drill bit having enhanced casing drill-out capability and improved directional stability Dec. 9, 2003
6655476 Earth boring bit Dec. 2, 2003
6629476 Bi-center bit adapted to drill casing shoe Oct. 7, 2003
6609580 Polycrystalline diamond compact insert reaming tool Aug. 26, 2003
6533048 Earth boring bit Mar. 18, 2003
6471445 Rotary displacement piling equipment Oct. 29, 2002
6464024 Bi-centered drill bit having improved drilling stability, mud hydraulics and resistance to cutter damage Oct. 15, 2002
6412579 Two stage drill bit Jul. 2, 2002
6397958 Reaming apparatus and method with ability to drill out cement and float equipment in casing Jun. 4, 2002
6394200 Drillout bi-center bit May. 28, 2002
6386302 Polycrystaline diamond compact insert reaming tool May. 14, 2002
6340064 Bi-center bit adapted to drill casing shoe Jan. 22, 2002
6298929 Bi-center bit assembly Oct. 9, 2001
6283231 Soil displacing screw auger and method for making a concrete pile with this auger Sep. 4, 2001
6269893 Bi-centered drill bit having improved drilling stability mud hydraulics and resistance to cutter damage Aug. 7, 2001
RE36817 Method and apparatus for drilling and enlarging a borehole Aug. 15, 2000
6076618 Rock drilling tool with radially extendable two-piece reamer Jun. 20, 2000
5992548 Bi-center bit with oppositely disposed cutting surfaces Nov. 30, 1999
5992547 Rotary drill bits Nov. 30, 1999
5931235 Cutter head, boring jig and device and process for sea bottom boring Aug. 3, 1999
5875860 Drill for making a pole in the ground and a method for applying such a drill Mar. 2, 1999
5803195 System, method and cutterhead for dry full-area drilling Sep. 8, 1998
5735360 Mining bit Apr. 7, 1998
5678644 Bi-center and bit method for enhancing stability Oct. 21, 1997
5497842 Reamer wing for enlarging a borehole below a smaller-diameter portion therof Mar. 12, 1996
5476149 Pilot bit Dec. 19, 1995
5456552 Method and apparatus for installing pipe in horizontal borehole Oct. 10, 1995
5445222 Whipstock and staged sidetrack mill Aug. 29, 1995
5433033 Excavating tooth and shank plate assembly Jul. 18, 1995
5427191 Auger head assembly and method of drilling hard earth formations Jun. 27, 1995
5417292 Large diameter rock drill May. 23, 1995

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