Sentence:  The drill press consists of a vertical shaft ( spindle ) which <WSD>is</WSD> tapered or threaded on one end to hold a drill chuck , a tubular housing ( quill ) in which the spindle is mounted , a head in which the quill is mounted , a feed lever which moves the quill up or down , a power source , and a movable table upon which the work is placed . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)