Crown Race Gears / Lapping

Crown Gear Process

Ring and Pinion Gear Lapping

Gear Lapping

Even with the most advanced CNC controlled gear cutting equipment, ring and pinion gears still end up with microscopic inconsistencies and variations that could create problems over time as the gears repeatedly rotate against each other. To remove these imperfections, the gears are properly aligned in another CNC machine where they are spun against each other with an abrasive compound that wears away any interferences. This process is called lapping and it permanently mates the two ring and pinion gears together as a matched pair.

Lapping is extremely effective at mating hypoid gears which is why all OEM and aftermarket automotive gears are lapped. Many manufacturers, however, rely on this process too heavily and use it to remove cutter marks leftover from gear cuttingand to correct errors in gear geometry. While lapping can be a cheap way to compensate for less precise cutting equipment, if used in this way, it will remove an excessive amount of the critical hardened gear case layer that then significantly reduces the strength and overall life of the gear.

Crown Race Gears uses lapping exclusively as a finishing process to pair the ring and pinion gears together. The process is continually monitored to make sure that only the imperfections and interferences are removed, preserving the heat treated gear case as much as possible. Then, rather than relying on lapping for the final gear tooth finish, Crown Race Gears follow the path used by the aerospace industry and Formula 1 racing teams with Isotropic Superfinishing (REM ISF). While this combination is more expensive and time consuming, it is the only way to maintain the maximum hardness and toughness of the gear while also achieving the smoothest and most consistent gear tooth finish.

Before moving on to Isotropic Superfinishing though, Crown Race Gears need to complete the heat treatment process by being slowly cooled to to below -300˚F in a process known as cryogenic treatment.

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