Gear Manufacture

This article discusses the different classes of gears, namely, spur, helical, herringbone, crossed-axes helical, worm, internal, rack, bevel, or face-type. It describes the methods used to cut the teeth of gears other than bevel gears: milling, broaching, shear cutting, hobbing, shaping, and rack cutting. The article also reviews the methods that are used to cut the teeth of bevel gears, such as face mill cutting, face hob cutting, formate cutting, helix form cutting, the Cyclex method, and template machining. The machining methods best suited to specific conditions are discussed. The article presents the factors influencing the choice of cutting speed and cutting fluids. It outlines two basic methods for the grinding of gear teeth: form grinding and generation grinding. The article concludes with information on the gear inspection techniques used to determine whether the resulting product meets design specifications and requirements.