There are no "perfect" 92 gear spheres. There will always be either a small gap between pitch circles or a slight phase error (or a combination of both). Presented here are some of my results for optimized 92 gear spheres with less than 0.0001° phase error (this does not take into account how tooth curvature might affect phase when there are pitch circle gaps). Solutions with minimal mating pitch circle gaps are shown first. Only gears with between 6 to 36 teeth were considered. The following solutions include 4 spheres with identical blue and yellow gears, 9 spheres with blue gears that are larger than the yellow gears, and 12 spheres with blue gears that are smaller than the red gears. No solutions were found with identical blue and red gears, unless you consider gaps of 30% tooth height or more. 25:33:27 takes the cake for least variation in diameter, while 30:36:8 has the most variation in diameter. I discovered these configurations on 9/22/11.
