End effector

An end effector for drilling and/or milling comprising a quill housing, a quill in the housing, a spindle rotatably supported in the quill for rotation about an axis, the quill being guided for axial reciprocation along the axis of the spindle, the spindle including an automatic tool clamp on an end thereof, a spindle drive shaft axially fixed and rotatably supported in the quill housing, a draw bar for opening and closing the automatic clamp, a rear end of the draw bar being telescoped in a forward end of the spindle drive shaft, the spindle drive shaft and the draw bar having central passages along their respective lengths and in communication with each other to supply coolant from a rear end of the spindle drive shaft to the automatic tool clamp, and a seal, disposed between an inside of the spindle drive shaft and an exterior of the draw bar to resist coolant leakage through telescoped areas of the spindle drive shaft and draw bar.