Worthen, William Ezra, 1819-1897, [from old catalog] ed · New York, Appleton · leaf 347
Fig. 709. Fig. 710. helical form of the thread of the screw. Usually the points of the teeth andbottoms of the spaces are formed of a concave outline, adapted to the convexity 330 MACHINE DESIGN AND MECHANICAL CONSTRUCTIONS. … of the screw, in order to pre-sent as much bearing surfaceas possible to its action. Inthis kind of gearing it is al-most invariably the screw thatimparts the motion. A screw is designated asright or left hand, according asthe forward motion is impartedby turning the screw to theright or left. In…
Mechanical drawing
Internet Archive · Library of Congress · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Graphophone patents] (1878)](https://img.insideoutlibrary.com/img/200/ia-graphophonepaten20unit-877-400.webp)
