Split block Bolts

K&B says to use carriage bolts for the split blocks. I couldn't find stainless steel carriage bolts so I settled on hex head bolts. How do I keep the bolt from turning when I tighten the knob, or heaven forbid, if the knob works it's way off and the bolt then falls on my primary? Glue? Silicone caulk?

I'm also having problems locating a machine threaded eye hook for use with the wheel barrel handles. I can find partially threaded ones, but not fully threaded.

Thanks

Jim
Try McMaster-Carr they have both. The eyebolts may have some unthreaded shank but they have a boatload of sizes to pick from and should be usable with a spacer if needed.
Hope this helps
Buck