A power tool comprising: a drive train including an output assembly, the output assembly including a spindle configured to support a tool element; a power source configured to selectively supply energy to the drive train to cause the output assembly including the spindle to rotate; a switch movable between a first position in which the power source does not supply energy to the drive train and a second position in which the power source supplies energy to the drive train; and a spindle lock configured to automatically engage the output assembly including the spindle when the switch is in the first position and to automatically disengage the output assembly including the spindle when the switch is in the second position, the spindle lock preventing rotation of the output assembly including the spindle when engaged; characterized by: an actuator configured to move the spindle lock, along an axis of rotation of the output assembly, between a first position in which the spindle lock is engaged with the output assembly and a second position in which the spindle lock is disengaged from the output assembly; wherein: the output assembly includes a plurality of teeth arranged around the axis of rotation of the output assembly; and the spindle lock includes one or more teeth configured to mesh with the plurality of teeth of the output assembly when the spindle lock is in the first position to prevent rotation of the output assembly. a drive train including an output assembly, the output assembly including a spindle configured to support a tool element; a power source configured to selectively supply energy to the drive train to cause the output assembly including the spindle to rotate; a switch movable between a first position in which the power source does not supply energy to the drive train and a second position in which the power source supplies energy to the drive train; and a spindle lock configured to automatically engage the output assembly including the spindle when the switch is in the first position and to automatically disengage the output assembly including the spindle when the switch is in the second position, the spindle lock preventing rotation of the output assembly including the spindle when engaged; characterized by: an actuator configured to move the spindle lock, along an axis of rotation of the output assembly, between a first position in which the spindle lock is engaged with the output assembly and a second position in which the spindle lock is disengaged from the output assembly; wherein: the output assembly includes a plurality of teeth arranged around the axis of rotation of the output assembly; and the spindle lock includes one or more teeth configured to mesh with the plurality of teeth of the output assembly when the spindle lock is in the first position to prevent rotation of the output assembly. an actuator configured to move the spindle lock, along an axis of rotation of the output assembly, between a first position in which the spindle lock is engaged with the output assembly and a second position in which the spindle lock is disengaged from the output assembly; wherein: the output assembly includes a plurality of teeth arranged around the axis of rotation of the output assembly; and the spindle lock includes one or more teeth configured to mesh with the plurality of teeth of the output assembly when the spindle lock is in the first position to prevent rotation of the output assembly. the output assembly includes a plurality of teeth arranged around the axis of rotation of the output assembly; and the spindle lock includes one or more teeth configured to mesh with the plurality of teeth of the output assembly when the spindle lock is in the first position to prevent rotation of the output assembly.