GB164388A - Method of making milling cutters - Google Patents

Abstract

164,388. Marks, E. C. R., (Pratt & Whitney Co.). Dec. 3, 1919. Milling-cutters; backing-off lathes.-Backed-off milling cutters of non-rectilinear contour are finished in a backing-off lathe by a narrow-pointed tool which is fed laterally through a distance less than its width for each rotation of the cutter blank. The relation between the backing-off action and the rotation of the blank is varied in accordance either with the longitudinal inclination of the teeth by utilizing the longitudinal feed of the tool carriage, or in accordance with the undercutting of the teeth, or both. Fig. 23 shows the apparatus diagrammatically. The backing- off cam 45 driven by worm gearing 51 and bevelgearing 52 from a shaft 48 operates a slide 40 carried on the main cross slide 39; the alteration in phase of the reciprocation is produced by means of a cam-slot connection 60 between the driving- sleeve 56 and the mandrel 55 under the control of an arm 58 attached to the carriage 38. In the case of undercut teeth the backing-off action is retarded by arranging the bevel-wheel 52 to slide on its shaft in unison with the main slide 39 and those driven by the shaft 50 through longitudinal cam-slots (not shown). Fig. 18 shows diagrammatically an apparatus for cutting radial teeth, the backing-off action of the tool S being effected by a cam 20 and the tool held parallel to itself as it follows the former 18. The position of the cam 20 is adjusted as the carriage moves along by a helical keyway 24 in the cam-shaft corresponding to the helical form of the teeth. Specification 164,387 is referred to.