Large FAT Counterweight Axle Size
My school is having a contest to throw 1 gallon jugs of water in a few months. I have designed a FAT with about 300lb of counterweight total, but I'm unsure of how large to make the CW axle. The arm is 4.5" wide, and the distance between the vertical supports is 18.5". Each support is 1.5" thick, so from counterweight bucket to counterweight bucket is 21.5", and I was planning on having each bucket about 12" wide. How thick of a steel axle am I going to need so that it doesn't deform after each throw?
Thanks for your help!