a method and apparatus for controlling the amount of row distortion before and dynamically during the lapping process used to manufacture sliders for magnetic storage devices . a wafer quadrant of slider rows is bonded to an extender tool held in a carrier assembly and an actuator is used to laterally apply force to the extender tool such that it changes the profile of the wafer quadrant , and thus the foremost slider row . multiple arms may be defined in the extender tool , permitting independent engagement with and application of the lateral force by the actuator . bending moments in each arm are then efficiently and controllably transferred into a beam in the extender tool which is proximate to the point where the wafer quadrant is bonded .