| CPC E21B 17/046 (2013.01) [E21B 17/0423 (2013.01)] | 20 Claims |

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1. A method to drill into a formation of the earth, the method comprising:
conveying a drilling assembly into a borehole, the drilling assembly comprising a tubular member and a drill bit, the drill bit being in contact with the formation;
rotating the drill bit with a shaft connected to the drill bit, the shaft comprising a first shaft member with a first engagement area and a second shaft member with a second engagement area, the first and second shaft members being configured to rotate within and relative to the tubular member, wherein at least one of the first and second engagement areas comprises one or more torsional locking elements;
engaging the first and second shaft members with each other by a threaded connection, the threaded connection is a connection with a compression element, and the compression element comprises a thread of the threaded connection; and
rotating the compression element to engage the first and the second engagement area with each other.
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