Worm Drives are used when the axis of rotation of a shaft must change direction. Being low-cost, potentially self-locking and providing high gear reductions, Worm Drives provide an effective means of decreasing speed whilst increasing torque.
A screw thread is a helical groove formed on an internal or external diametrical surface and is described by various terms including pitch, root, crest, flank and major diameter. These terms are described here.
A screw is a mechanical system that converts rotational motion in to linear motion. In other worlds it converts rotational force (torque ) in to a linear force. Here the resultant axial force due to an input torque is calculated from first principles.