I have the wire and pliers for safety wiring fastners, used to use them quit a bit 20+ years ago...
The "jam nut" proceedure works really well. In recent years I've been using the "green" Thread Locker by Loctite in situations like this. Doesn't require heat or excessive force to remove the fastner. In areas subject to a lot of vibration like chainsaws, motorcycles, outboards, etc, using silicon sealer on the threads will keep the bolts and or nuts from getting loose.
The spring over the bolt keeps the threads of the bolt under a little tension at all times, Like the previous post said, acting like a shakeproof washer if you will. My tractor has the bolt-flat washer-then spring set-up.
Is the job done yet?....just kidding, Lloyd