Abstract: A clock head assembly intended for vertical engagement to a disc in a disc drive for purposes of providing an arrangement of precise timing marks on the disc for use by a servo-writer. The clock head assembly includes a slider of the 50% or 30% size and a spacer adhesively attached to the upper surface thereof. In order to minimize stresses induced in the slider by the adhesive bonding, and to ensure that the clock head is capable of correct flying performance relative to the disc, the present invention envisions that the spacer surface bonded to the slider, or slider bonding surface, has dimensions substantially half the size of the dimensions of the surface of the slider to which the spacer is bonded. In another aspect of the invention, the spacer is designed to be suitable for large batch production.