A power rotary hand tool comprising: a drive shaft connected to a drive gear; a drive link having a body with an opening; a bushing disposed within the opening and configured to receive a crank pin and configured to transfer oscillatory movement from a crank pin to the drive link; a pair of opposing pawls (18, 20) pivotally connected to the drive link, each pawl operatively engageable with the drive gear to rotate the drive shaft in response to oscillatory lateral movement of the drive link; and characterised in that the tool further comprises a two-piece planet carrier comprising: a drive portion having an axis of rotation and fixedly mountable to a motor rotor of the tool; and a pinned portion including a base and a crank pin extending eccentrically from the base into the bushing, the crank pin having a center axis and operatively connectable to the drive shaft to provide rotation and torque to the drive shaft upon orbital rotation of the crank pin about the drive portion axis of rotation, the pinned portion rotatably engaged with the drive portion such that rotation of the rotor will cause the drive portion and the pinned portion to rotate relative to each other as a function of a load applied to the drive shaft such that an offset between the crank pin center axis and the drive portion axis of rotation is variable as a function of the load applied to the drive shaft, wherein the variance of the offset will vary a rotational speed and an amount of torque delivered to the drive shaft as a function of the load at drive shaft; and wherein the pinned portion is rotatably disposed within a receptacle eccentrically disposed within a head of the drive portion such that the pinned portion will rotate within the receptacle as a function of the load on the drive shaft, thereby varying the offset between the crank pin center axis and the drive portion axis of rotation as a function of the load on the drive shaft, and affecting the speed of rotation and the amount of torque delivered to the drive shaft. a drive shaft connected to a drive gear; a drive link having a body with an opening; a bushing disposed within the opening and configured to receive a crank pin and configured to transfer oscillatory movement from a crank pin to the drive link; a pair of opposing pawls (18, 20) pivotally connected to the drive link, each pawl operatively engageable with the drive gear to rotate the drive shaft in response to oscillatory lateral movement of the drive link; and characterised in that the tool further comprises a two-piece planet carrier comprising: a drive portion having an axis of rotation and fixedly mountable to a motor rotor of the tool; and a pinned portion including a base and a crank pin extending eccentrically from the base into the bushing, the crank pin having a center axis and operatively connectable to the drive shaft to provide rotation and torque to the drive shaft upon orbital rotation of the crank pin about the drive portion axis of rotation, the pinned portion rotatably engaged with the drive portion such that rotation of the rotor will cause the drive portion and the pinned portion to rotate relative to each other as a function of a load applied to the drive shaft such that an offset between the crank pin center axis and the drive portion axis of rotation is variable as a function of the load applied to the drive shaft, wherein the variance of the offset will vary a rotational speed and an amount of torque delivered to the drive shaft as a function of the load at drive shaft; and wherein the pinned portion is rotatably disposed within a receptacle eccentrically disposed within a head of the drive portion such that the pinned portion will rotate within the receptacle as a function of the load on the drive shaft, thereby varying the offset between the crank pin center axis and the drive portion axis of rotation as a function of the load on the drive shaft, and affecting the speed of rotation and the amount of torque delivered to the drive shaft. a drive portion having an axis of rotation and fixedly mountable to a motor rotor of the tool; and a pinned portion including a base and a crank pin extending eccentrically from the base into the bushing, the crank pin having a center axis and operatively connectable to the drive shaft to provide rotation and torque to the drive shaft upon orbital rotation of the crank pin about the drive portion axis of rotation, the pinned portion rotatably engaged with the drive portion such that rotation of the rotor will cause the drive portion and the pinned portion to rotate relative to each other as a function of a load applied to the drive shaft such that an offset between the crank pin center axis and the drive portion axis of rotation is variable as a function of the load applied to the drive shaft, wherein the variance of the offset will vary a rotational speed and an amount of torque delivered to the drive shaft as a function of the load at drive shaft; and wherein the pinned portion is rotatably disposed within a receptacle eccentrically disposed within a head of the drive portion such that the pinned portion will rotate within the receptacle as a function of the load on the drive shaft, thereby varying the offset between the crank pin center axis and the drive portion axis of rotation as a function of the load on the drive shaft, and affecting the speed of rotation and the amount of torque delivered to the drive shaft.