A spindle assembly for a machine tool wherein a rear end portion of the
spindle is structured to allow the spindle to be operated at higher
speeds, thereby enhancing precision. The spindle assembly includes a
spindle mounted within a spindle housing able to undergo rotation by a
rotor and bearings. A collet directly secures and releases a tool inside
the spindle. A draw bar, one end of which is connected to the collet
through a sleeve within the spindle, operates the collet. A piston and
cylinder connected to the draw bar moves the draw bar in forward and
reverse directions. A rotary joint supplies cutting oil to the spindle. An
adapting arrangement connects a rear end of the draw bar and the rotary
joint to allow forward and reverse movement with respect to the spindle.
