Learning the Ropes
LOL, I went through a search for such u-bolts a couple of years ago myself, but they seem to be made for specific applications and not many to be found for general use. I did find a few at Fastenal, but none were long enough for my use. I ended up making my own, but it's a tedious job to untemper, then flatten the radius, then re-temper them just right. Also had to make a jig to use in my english wheel to flatten the radius without scoring my dies. If you have a bead roller that will work, too, if the radius of your u-bolts is large enough. Tempering and hardening is the hard part for most guys. Takes time and a ceramic kiln to do the job properly.