as the drill 36 has cleared the workpiece 100 during the retraction stroke the first tool holder 32 may commence retraction at step 124 thereby unclamping the workpiece 100 as shown at step 126 finally with a hole having been drilled in the workpiece 100 at the target location spindles 24 and 26 can be moved along with their respective tool holders 32 34 to the next target hole location the embodiments of the disclosure described above may be used in an aircraft manufacturing and service method 130 as shown in fig2 and an aircraft 160 as shown in fig2 during pre production exemplary method 130 may include specification and design 132 of the aircraft 160 and material procurement 134 during production component and subassembly manufacturing 136 and system integration 138 of the aircraft 106 takes place thereafter the aircraft 160 may go through certification and delivery 140 in order to be placed in service 142 while in service by a customer the aircraft 160 is scheduled for routine maintenance and service 144 which may include modification reconfiguration refurbishment and so on each of the processes of method 130 may be performed or carried out by a system integrator a third party and or an operator e g a customer for the purposes of this description a system integrator may include without limitation any number of aircraft manufacturers and major system subcontractors a third party may include without limitation any number of venders subcontractors and suppliers and an operator.