[EricVanWyk]

Thanks for all the insight, and apologies for latency in this response. I wanted to be sure I knew a little more before responding, but I haven't been able to pull more information or pictures up on/of our specific failure. The busted-box is in "a bag somewhere over there". Which, "there" they mean, I do not know.

The spindle was mounted directly on the gearbox output, but it was supported on the other side by a pillow block: A single plate held the gear box (4 mounting holes) and the pillow block (2 mounting holes).


I'd like to convert this thread into an "Idiots Guide to Torque" or a "Mentor's Guide to Teaching Torque", if possible. My vision of it is the following:
* A spread sheet similar to Dick Lynn's information for the N most commonly used gearboxes in FRC ((85 ft lbs for a P80)).
* A simple beam bending stress calculator, per Joe Johnson's suggestion, with perhaps 3 example gearboxes already entered. This will probably benefit from a picture of a gear with the important dimensions labeled.
* An explanation of when the simple beam calculator is appropriate, and pointers towards how to do it more accurately. Maybe this is where we mention the life cycle calculations?
* An explanation of how "how's" matter. For example, pictures of busted gears and how they failed. "Gears look like this? Too much side load!" "Gears look like that? Need more lube!" etc.

Thanks again, all, and I'll try to take pictures after ATL.

EDIT/PS:
When I teach a new topic at FRC, I usually give a 2-10 minute "whats up" to everyone, and then point 1 or 2 students in the right direction to dig deeper. If this resource could be architected similarly, that would be fantastic.