What about star washers? Where you drill the hole and knock the tabs in then fold the remaining tabs around the bolt faces.. We have roller conveyors at work, the bolts kept undoing on the side where the roller direction counters the thread direction causing it to come undone when the bearings were starting to get a little worse for wear.. I realise it would be best to replace a roller everytime you come across this but it becomes a pita when sh*t gets busy. I tried spring washers, locktite, wire through the bolt holes (caused them to shear more often), then the star washers. Bend 4 tabs up and 2 tabs into the drilled holes. The bolts dont undo themselves anymore they just shear off when the bearings are totally farked.