Fig. (11) Relations between the hydrostatic bearing recess pressure, oil velocity and the spindle rotation speed: (a) the radial hydrostatic bearing recess pressure and the negative pressure near the oil return tank; (b) the thrust hydrostatic bearing recess pressure and the entrance negative pressure; (c) the radial hydrostatic bearing recess oil velocity and the spindle rotation speed; (d) the thrust hydrostatic bearing recess oil velocity and the spindle rotation speed.