A method is provided for achieving final air gap and parallelism of a control valve of a fuel injector, the control valve having a body defining an transverse top face and including a thick disc magnetic armature having a planar transverse upper face. The method includes a) measuring the actual position from the armature upper face and the body top face and, determining the actual parallelism error between said faces; and b) ablating the armature to generate an ablated upper face parallel to the body top face, the distance from the ablated upper face to the body top face being a final air gap.