In surfing Endless-Sphere.com, I noticed that there was some discussion about lock-nuts not working in holding ebike motors on rear dropouts. I noticed this the last time I took off the rear motor. I noticed that both nuts were fairly loose when I had actually cranked them down pretty hard when installing them. In this discussion, there was mention of a unique lock washer that actually would not come loose, until typical flattened lock washers.
As you probably know, lock washers have a split in them which acts as the source of friction between the nut and the mounting surface. However, when the lock washer is compressed, as it is when it's under pressure under a nut, the friction from the split is nonexistent since the washer is flattened. It does not do any locking when compressed!
What was discussed is the Nord-Lock washer.
The Nord-lock is unique in that it not only has serrations on the top and bottom mating surfaces, but there are cams cut in between the two mating washers. The cam angle is greater than the thread angle so it is the force needed to loosen it is extremely high and it's difficult to loosen it even under intense vibration. Here's the product demo video.
I ordered two pairs of Nord-locks from ES. The thread is here:
When shopping around for these, I found that they were very expensive to buy in small quantities so I am very grateful to Shiny for buying these in bulk and splitting them up for smaller quantity sales to us.
I hope to mount these the same time I mount Doctorbass's torque arms on my bike.