hammasratta hammaste rullumismeetodil lõikus hambafreespinkidel, kasutades tigufreese (vt rullumismeetod; tigufrees), gear cutting by use of a tool resembling a worm gear in appearance, having helically spaced cutting teeth; in a single-thread hob, the rows of teeth advance exactly one pitch as the hob makes one revolution; with only one hob, it is possible to cut interchangeable gears of a given pitch of any number of teeth within the range of the hobbing machine (see: gear generating; hob)