They call out those cheap, split lockwashers that have been experimentally proven to be ineffective: https://i.imgur.com/4nbgxmW.jpg https://i.imgur.com/4nbgxmW

They call out those cheap, split lockwashers that have been experimentally proven to be ineffective: https://i.imgur.com/4nbgxmW.jpg https://i.imgur.com/4nbgxmW.jpg The lockwasher serves as a spring while the bolt is being tightened. However, the washer is normally flat by the time the bolt is fully torqued. At this time it is equivalent to a solid flat washer, and its locking ability is nonexistent. In summary, a Iockwasher of this type is useless for locking. Also, note this PDF was posted to HN six years ago: https://news.ycombinator.com/item?id=8604761 https://news.ycombinator.com/item?id=8604761