may be any device that it is adjustable for example a switch a trimmer condenser a device for selecting a resistance by means of a short plug or the like or a device for effecting the trimming by means of a laser may be alternatively used in other words any form or method can be available description will be now made on a floppy disk unit according to the second embodiment of the invention component elements of the second embodiment which may be the same with those of the aforesaid embodiment are designed by the same reference numerals and description thereof will be omitted fig4 to 6 show the essential portions of a bearing for a spindle motor in the second embodiment also in this embodiment a support plate 6 is formed therein with a fitting hole by means of press work so that a shear droop portion 61 is formed along the periphery of the fitting hole of the support plate the support plate 6 is formed on the upper surface thereof with a printed circuit board pcb 26 a bearing member 170 is made of a copper base sintered alloy and is generally in a stepped cylindrical shape that is provided in its upper part with a large diameter portion 171 which has an outside diameter larger than the diameter of the fitting hole of the support plate and with a small diameter portion 172 which is to be fitted in the fitting hole of the support plate further similarly to the first embodiment a ring like caulking portion 173 is formed at the lower end of the small diameter portion 172.