Worm gearing
Hugh Kerr Thomas's Worm Gearing, published by McGraw-Hill in New York in 1913, is a technical manual on the design and cutting of worm gears for machine-shop engineers and draughtsmen. The plates are line diagrams: thread profiles with hatched flanks, helix-angle triangles, arcs swept from radii, and Greek-lettered dimension arrows, useful as precise geometric line art and annotation styles.
