The present disclosure is directed to a gearbox repair apparatus for repairing a bore hole of a gearbox torque arm. In certain embodiments, the apparatus includes a mounting structure configured to mount to the torque arm. The mounting structure includes a through hole that aligns with the bore hole of the torque arm when mounted thereto. As such, when mounted to the torque arm, the mounting structure is configured to locate a boring bar at a center of the bore hole such that the boring bar is perpendicular to a face of the torque arm. Further, the mounting structure is configured to receive the boring bar through the aligned through hole and bore hole such that, when inserted therethrough, the boring bar is configured to machine and thus repair the bore hole.

A reverse spot-facing tool for cutting a reverse spot-face in a workpiece using a reverse spot-facing cutter configured to engage a pilot shaft having a first end and a second end is disclosed. The workpiece comprises a through hole having a central axis. The reverse spot-facing tool comprises a stop configured to be located between the first end and the second end of the pilot shaft; a biasing assembly that generates a first thrust force and an equal and opposite second thrust force when the reverse spot-facing cutter is cutting the reverse spot face; and a thrust bearing configured to be positioned between the biasing assembly and the stop. When the reverse spot-facing cutter is cutting the reverse spot-face, the thrust bearing transmits the second thrust force from the biasing assembly to the stop, and the biasing assembly transmits the first thrust force to the workpiece.

A reverse spot-facing tool for cutting a reverse spot-face in a workpiece using a reverse spot-facing cutter configured to engage a pilot shaft having a first end and a second end is disclosed. The workpiece comprises a through hole having a central axis. The reverse spot-facing tool comprises a stop configured to be located between the first end and the second end of the pilot shaft; a biasing assembly that generates a first thrust force and an equal and opposite second thrust force when the reverse spot-facing cutter is cutting the reverse spot face; and a thrust bearing configured to be positioned between the biasing assembly and the stop. When the reverse spot-facing cutter is cutting the reverse spot-face, the thrust bearing transmits the second thrust force from the biasing assembly to the stop, and the biasing assembly transmits the first thrust force to the workpiece.

A reverse spot-facing tool for cutting a reverse spot-face in a workpiece using a reverse spot-facing cutter configured to engage a pilot shaft having a first end and a second end is disclosed. The workpiece comprises a through hole having a central axis. The reverse spot-facing tool comprises a stop configured to be located between the first end and the second end of the pilot shaft; a biasing assembly that generates a first thrust force and an equal and opposite second thrust force when the reverse spot-facing cutter is cutting the reverse spot face; and a thrust bearing configured to be positioned between the biasing assembly and the stop. When the reverse spot-facing cutter is cutting the reverse spot-face, the thrust bearing transmits the second thrust force from the biasing assembly to the stop, and the biasing assembly transmits the first thrust force to the workpiece.

A reverse spot-facing tool for cutting a reverse spot-face in a workpiece using a reverse spot-facing cutter configured to engage a pilot shaft having a first end and a second end is disclosed. The workpiece comprises a through hole having a central axis. The reverse spot-facing tool comprises a stop configured to be located between the first end and the second end of the pilot shaft; a biasing assembly that generates a first thrust force and an equal and opposite second thrust force when the reverse spot-facing cutter is cutting the reverse spot face; and a thrust bearing configured to be positioned between the biasing assembly and the stop. When the reverse spot-facing cutter is cutting the reverse spot-face, the thrust bearing transmits the second thrust force from the biasing assembly to the stop, and the biasing assembly transmits the first thrust force to the workpiece.