a mode selection apparatus for a jigsaw having scrolling and orbital modes is disclosed . the mode selection apparatus comprises a locking arm moveable between a first position in which a scroller knob is rotatable relative to the tool housing , a second position in which the locking arm engages the scroller knob to prevent it from rotating relative to the tool housing and an output shaft of the jigsaw is prevented from pivoting about a pivot axis transverse to the longitudinal axis of the output shaft , and a third position in which the scroller knob is prevented from rotating relative to the tool housing and the output shaft is causes to pivot about the pivot axis . the locking arm has a slot for engaging a tooth on a scroll selector for moving the locking arm between the first , second and third positions thereof . the tooth remains in engagement with the slot during movement of the locking arm between the first , second and third positions .