Abstract: A lapping plate is selectively textured for improved useful life and greater abrading consistency. Glass beads are serially propelled onto a lapping surface of the lapping plate in order to form spherical cavities of generally uniform size and distribution, and of a desired density. The cavities provide discontinuity in the lapping surface which substantially prevents workpiece hydroplaning. The cavities also receive loose abrading grit, workpiece fragments and other contaminants, resulting in more smoothly machined workpiece surfaces. Use of the lap plate with cavities also has been found to improve the co-planarity of composite magnetic transducing heads.

Abstract: A wiper guide assembly, mounted at the free end of a workpiece carrying arm, can be selectively released to position a neoprene wiper blade against a lapping surface, and retracted whereby the blade is lifted away from the lapping surface. The wiper blade is located just ahead of a workpiece supported by the arm, and between the workpiece and a source of abrasive slurry supplied to the lapping surface. When retracted, the wiper blade is spaced apart from the lapping surface to expose its associated workpiece to the abrasive slurry, permitting more rapid removal of material. When the assembly is released, the wiper blade contacts the lapping surface in a wiping engagement, to guide or divert slurry away from the workpiece, whereby the lapping surface contiguous with and about the workpiece is comparatively free of abrasive slurry.

Abstract: A lapping plate is selectively textured for improved useful life and greater abrading consistency. Glass beads are serially propelled onto a lapping surface of the lapping plate in order to form spherical cavities of generally uniform size and distribution, and of a desired density. The cavities provide discontinuity in the lapping surface which substantially prevents workpiece hydroplaning. The cavities also receive loose abrading grit, workpiece fragments and other contaminants, resulting in more smoothly machined workpiece surfaces. Use of the lap plate with cavities also has been found to improve the co-planarity of composite magnetic transducing heads.

Abstract: An enclosed slurry dispensing system employs a sealed pressurized reservoir for supplying slurry through a bypass chamber to a dispensing nozzle. Excess slurry is bypassed through the bypass chamber to an intermediate chamber. Slurry is allowed to return to the reservoir through a normally-closed check valve, closed by the higher pressure of the reservoir. The system is purged by opening the reservoir to the atmosphere, creating a sub-atmospheric pressure in the bypass chamber. Air is admitted through the nozzle to purge the nozzle of slurry. At the same time, the check valve opens and excess slurry returns to the reservoir from the intermediate chamber.

Abstract: A method of calibrating an analog machining sensor of the varying resistance type which has been deposited on a surface involves depositing adjacent it with great positional accuracy relative to a feature on the surface, discrete machining sensors. As machining takes place, the discrete sensor's continuities are successively broken as the analog sensor's height is reduced and its resistance increased. Measuring the resistance of the analog sensor at the time each discrete sensor breaks yields values from which the position of the analog sensor's machined edge can be very accurately related to the position of the feature on the surface.

Abstract: Apparatus for precisely machining the surface of a workpiece comprises a rotating plate with a flat, horizontal abrasive-laden surface against which the workpiece surface is forced by gravity. The workpiece is carried on the free end of an arm pivotably supported remote from the end of the arm carrying the workpiece. Loading of the workpiece work surface can be varied by shifting weights along the length of the arm or transverse to the length of the arm. The workpiece itself can comprise a bar on which several magnetic transducing heads have been deposited. Machining the workpiece surface to a preferred position accurately defines a dimension of choice, such as the throat height of these transducers.

Abstract: A workpiece carrier includes a flat support surface to which a workpiece is attached by bonding. The carrier includes means for bending the carrier support surface so that it becomes concave. When dealing with a relatively flexible workpiece, one can cause the workpiece's surface to be machined to attain a convex shape by bending the support surface of the carrier concavely, and then bonding the workpiece attachment surface to the carrier while the carrier support surface is concavely bent. Allowing the carrier's support surface to assume a less concave shape then imparts a convex shape to the surface of the workpiece to be machined.

Abstract: A workpiece carrier has a support bar centrally supported at one end of a stem portion. The stem is carried at its opposite end on a base. Columns are interposed between the ends of the support bar and the base. Heat is applied to the columns, preferably by resistive heating elements, to heat them and cause their thermal expansion, causing the support bar ends to be bent away from the base. A relatively flexible workpiece which has been bonded to the support arms on a surface facing away from the base will undergo the same bend.

Abstract: Apparatus for mounting a thin flexible grinding wheel to allow accurate cutting of kerfs therewith. A method of precision assembly of the apparatus is also disclosed.

Abstract: A magnetic transducing core having a transducing face defined by planes whose surfaces comprise substantially parts of ferrite grains, and a method for producing this core. The method involves proper selection of the grit size and binder of a diamond grinding wheel, machining its sides to precise parallelism with each other, mounting it on a highly accurate air bearing, rotating it at high speed, and feeding a work piece ferrite bar from which the core is cut into the rotating wheel. These techniques prevent axial run-out between the edge of the cutting portion of the wheel and the work piece greater than 2.5 microns. A preferred embodiment includes a high pressure jet of coolant impinging on the wheel just ahead of the cutting interface.

Abstract: Apparatus for mounting a thin flexible grinding wheel to allow accurate cutting of kerfs therewith. A method of precision assembly of the apparatus is also disclosed.

Abstract: A magnetic head is manufactured by depositing a layer of spacer material onto the facing surfaces of the magnetic cores; the thickness of each layer being approximately one-half the length of the intended gap and the thicknesses of both layers together being approximately equal to the thickness (length) of the gap. A layer of bonding glass is deposited onto the surfaces of the spacer layers and the cores are pressed together at an elevated temperature to fuse the glass layers and extrude most of the glass.