A gear ring this size cannot be cast to final form, pressed or ground from solid. It has to be generated, one conjugate stroke at a time. Gear shaping works on a deceptively elegant principle: the cutter is itself a gear. Hardened and relief-ground on every flank, it is rolled against the blank by the machine exactly as though the two were already in mesh. Each stroke shears metal; between strokes, both cutter and workpiece index by a fraction of a tooth. The involute flank is never traced from a template. It emerges as the envelope of several hundred straight cutting edges sweeping the same volume of space. What makes the process work at this scale: - The cutter retracts a fraction of a millimetre on the return stroke. Without that relief, the flanks would rub on the way back up and burnish the freshly cut surface into a smeared, work-hardened mess. - Depth is taken in passes. A coarse module ring of this class carries a whole tooth depth of well over 50 mm, far beyond what any sin...