[fox46]

All we had were some hand drawings when we built these but all the information is there to reverse engineer it. I'll see if I can find and scan them tomorrow- I think they are still floating around the shop.

No modification to any machine will eliminate the chance of failure. Shifting the failure mode to a stronger part of the mechanism was exactly what we wanted to accomplish. Planetary gear trains are incredibly robust. I suspect the method of failure is now the interferance fit of the sungear that drives the final reduction pressed into the 3rd reduction's carrier. In any case, it is much much stronger and can now be used as it was initially marketed to us.

I have no doubt that this thread will quickly accumulate posts accusing teams of having poor designs or not using the boxes correctly but the undeniable fact of the matter is this: The Banebot P60 has a factor of safety of less than one, even for the pint-size RS395. The factor of safety decreases the larger the motor you put on it. No machine such as these gearboxes should ever be designed with a FOS of less than 1. As Kevin just mentioned, very few people are actually exceeding the ultimate strength of the unit, they are only comming very close to it so the failure mode presented seems to be more of a fatigue/degradation issue. Most people are just "marginally" exceeding the P60 capacities so even if these mods only added 10% more strength it is most likely enough to solve the problem

FYI: Banebots now have a P60 gearbox offering 627:1
Edit: correction- it's 672:1! (thank you dislexia) I guess a suitable application for this would be powering a large clock?