A reaction tool for forming openings in an aircraft fuselage joint is provided. The joint includes (i) a first side from which a forming tool is to be applied at a plurality of opening locations and (ii) an opposing second side. The reaction tool includes a plurality of connectors configured to couple to the joint second side, and a reaction bar coupled to the plurality of connectors. The reaction bar is configured to extend across the plurality of opening locations. The reaction tool also includes a plurality of reaction members coupled to the reaction bar. Each of the reaction members includes a clamping surface configured to couple to the joint second side such that each clamping surface at least partially surrounds a corresponding one of the plurality of opening locations.

The machine tool 1 for machining a hole 3a of a desired size in a workpiece 3, includes: a main shaft 30 holding a tool 2; a spindle unit 40 including a spindle 41 which holds the shaft 30 rotatably on the axis r of rotation, and a housing 42 which covers the periphery of the spindle 41; a drive unit 50 for holding the unit 40 tiltably with respect to the workpiece 3 held by a holder 20, and for moving the unit 40 relative to the workpiece 3; a mount 70 extending from the housing 42 toward the periphery of the shaft 30; and a control section 90 which, based on the results of measurement by distance measurement sensors 82 held by the mount 70, controls the unit 50 so as to correct the inclination of the shaft 30 with respect to the workpiece 3.

The machine tool 1 for machining a hole 3a of a desired size in a workpiece 3, includes: a main shaft 30 holding a tool 2; a spindle unit 40 including a spindle 41 which holds the shaft 30 rotatably on the axis r of rotation, and a housing 42 which covers the periphery of the spindle 41; a drive unit 50 for holding the unit 40 tiltably with respect to the workpiece 3 held by a holder 20, and for moving the unit 40 relative to the workpiece 3; a mount 70 extending from the housing 42 toward the periphery of the shaft 30; and a control section 90 which, based on the results of measurement by distance measurement sensors 82 held by the mount 70, controls the unit 50 so as to correct the inclination of the shaft 30 with respect to the workpiece 3.