a screw - type draincock assembly in which separate body and stem parts are each integral elements and in which the body part provides an external seat and the stem part provides a transverse handle . the valve assembly is preferably formed by initially arranging a head portion of the valve stem to pass through the threaded bore and external seat of the body and , subsequent to assembly of the stem in the body , plastically flaring the head portion to a configuration adapted to seal the external body seat .