A handheld, powered tool device comprising: a housing with a forward gear case, the forward gear case including an upper cover section and a lower cover section, the lower cover section including a neck secured to the upper cover section via a cover flange; a motor disposed within the housing; a tool assembly including a spindle for supporting a working tool operable to act on a work surface, the spindle being driven by the motor; a shield assembly coupled to the forward gear case selectively rotatable relative to the tool comprising a guard member operable to deflect debris generated by the working tool and a coupling member to couple the guard member to the neck of the forward gear case of the housing; and a lock mechanism which co-operates with the shield assembly to secure rotational position of the shield assembly and which comprises a pawl pivotally coupled to a flange of the lower cover section of the gear case of the housing, the lock mechanism operable to secure the rotational position of the guard with respect to the neck of the gear case of the tool, characterised in that the shield assembly further comprises an actuator movable relative to the tool housing wherein the actuator is rotatable about the coupling member; an alignment system in communication with the coupling member and the actuator, wherein the alignment system is operable to orient the actuator in a predetermined position relative to the coupling member; wherein the actuator comprises a plurality engagement notches angularly spaced about the actuator; the coupling member comprises a plurality of windows; and the alignment system aligns each of the plurality of engagement notches with a corresponding window on the coupling member; wherein the pawl includes a first boss to engage an engagement notch and a second boss configured to engage a window of the coupling member; wherein the actuator extends outward to an outer periphery of the tool so that the actuator can be moved relative to the guard member and coupling member of the tool by forceful contact of an external object; and wherein the forceful contact also unlocks the locking mechanism permitting the guard to rotate and rotates the guard relative to the tool, wherein the lock mechanism is operable to secure the shield assembly in a selected rotational position with respect to the spindle; and moving the actuator with respect to the coupling member releases the lock mechanism to permit rotation of the shield assembly about the spindle. a housing with a forward gear case, the forward gear case including an upper cover section and a lower cover section, the lower cover section including a neck secured to the upper cover section via a cover flange; a motor disposed within the housing; a tool assembly including a spindle for supporting a working tool operable to act on a work surface, the spindle being driven by the motor; a shield assembly coupled to the forward gear case selectively rotatable relative to the tool comprising a guard member operable to deflect debris generated by the working tool and a coupling member to couple the guard member to the neck of the forward gear case of the housing; and a lock mechanism which co-operates with the shield assembly to secure rotational position of the shield assembly and which comprises a pawl pivotally coupled to a flange of the lower cover section of the gear case of the housing, the lock mechanism operable to secure the rotational position of the guard with respect to the neck of the gear case of the tool, characterised in that the shield assembly further comprises an actuator movable relative to the tool housing wherein the actuator is rotatable about the coupling member; an alignment system in communication with the coupling member and the actuator, wherein the alignment system is operable to orient the actuator in a predetermined position relative to the coupling member; wherein the actuator comprises a plurality engagement notches angularly spaced about the actuator; the coupling member comprises a plurality of windows; and the alignment system aligns each of the plurality of engagement notches with a corresponding window on the coupling member; wherein the pawl includes a first boss to engage an engagement notch and a second boss configured to engage a window of the coupling member; wherein the actuator extends outward to an outer periphery of the tool so that the actuator can be moved relative to the guard member and coupling member of the tool by forceful contact of an external object; and wherein the forceful contact also unlocks the locking mechanism permitting the guard to rotate and rotates the guard relative to the tool, wherein the lock mechanism is operable to secure the shield assembly in a selected rotational position with respect to the spindle; and moving the actuator with respect to the coupling member releases the lock mechanism to permit rotation of the shield assembly about the spindle.