the spiral part of a screw is called shaft.
what is the spiral part of a screw called?
shaft
section::::spiral fluted extractor.





















































a spiral screw extractor is itself a coarse-pitched tapered screw thread. they are generally left-handed, for use on right-handed threads, though there are right-handed extractors for removing left-handed screws.





















































the screw is first drilled out to the proper diameter for that extractor. the extractor is then inserted into this hole and turned in the direction opposing the stuck screw's original one, usually using a tap wrench. as the extractor is turned, the flutes on the tool dig into the screw, causing it to lock tightly and withstand the applied torque required to remove the screw.
screw extractor
the force and torque vectors that arise in applying newton's laws to a rigid body can be assembled into a screw called a wrench. a force has a point of application and a line of action, therefore it defines the plücker coordinates of a line in space and has zero pitch. a torque, on the other hand, is a pure moment that is not bound to a line in space and is an infinite pitch screw. the ratio of these two magnitudes defines the pitch of the screw.





















































section::::basic concepts.:twist.
screw theory