2. Generation trimming 2.1 Rack and pinion hobbing The most common machines used in industry are MAAG and Sunderland machines. We will study the kinematic chain of the MAAG machine. Figures 6a and 6b show two types of machine respectively: a) type SH 75 (∅ 750 mm); b) type SH 600 (∅ 6 000 mm) for high power ratings.