and a stick shaped for the housing are bonded to each other ten fine machined after the fine machining the bar is cut into individual magnetic head sliders application_number US 97096897 A description the first embodiment of the present invention will be described as follows by reference to explanatory views a ferrite core is constituted by two parts so called i bar 1 and c bar 2 also called u u00b0 bar so as to form a read write gap of sub micron order fig1 shows the substrate state of the two parts respectively fig2 is a diagram showing a state that grooves 3 for coil wiring are formed on opposite surfaces of the respective substrates and an apex fig1 reference numeral 22 being datum in depth direction of the read write gap is formed the provision of the grooves and the formation of the apex result in that the i bar 1 and the c bar 2 are joined and then machined during grinding work simultaneously on the same jig thereby deviations from the pitch distance generated due to abrasion vibration or the like of the grindstone during grinding can be canceled and the deviation accuracy of glass bond hereinafter described can be improved after the groove is provided and the user is formed as shown in fig3 in order to generate a strong magnetic field in the read write gap a metal thin film 4 made of iron and a glass film 5 of non.