A spindle stock unit for surface grinding machines includes a spindle head, and a spindle assembly having a spindle body rotatably supported by a pair of axially spaced radial fluid bearings in the spindle head and positioned in place by a pair of axially spaced thrust fluid bearings in the spindle head. To minimize thermal displacement of the spindle assembly in an axial direction, the spindle body is made of crystallized glass of low coefficient of thermal expansion.