Im finding some really cool fasteners.... The V-dub exaust studs are 6m x1.0 ... Those nos nuts are a pinch type of lock nut... Some of the rice burners have some different styles also...
If you search YouTube using these keywords (ave boltr lock washers) you should find a video he's done that refers to lock washers and split washers etc... And how they don't do anything extra that a normal washer and the fastener being torqued properly. The sweet spot to achieve is where the threads start to flex a little. Which is a bit below the point where the threads start to fatigue and strip off. The torque limits that get listed on critical bolts, nuts, etc... Represents this limit where it cannot reliably be pushed passed that limit without potentially causing a failure. And a good way to tell if a bolt or nut has been pushed passed that threshold and needs to be replaced is to find a new nut or bolt and see if it can travel easily along the threads. If it gets stuck or tightens up then it's damaged and should be replaced. Also if you see slivers of spiraling metal inside a nut or falls away from the bolt that's your threads that has detached not a built in spring lol.
You can also look up how the army studied the washers, all because of improper torque. Since they couldn't control intelligence in the army, they switched to star locks( and also whizlocks, which really people should just use a whizlock, so easy a cave man can use them). Even a drug addict convict who joined, can use one of those. lol. I never had a problem with split lock washers. They work fine for me. Most people weren't in the fastener industry like I was for almost a decade though. I always say, go with what works, but most people don't know how to use them properly. An reusing them after torqueing them down, well they can't really be reused and must be replaced afterwards( another problem the multimillion dollar army study found). Most people run into problems, after reusing them. It's not the lock washer, it's the way they are being used.
They make those now, the pinched nut, they call them crown locks. Usually have three dimples on the outside face to show they are a crown lock nut. The problem with those, to many off and on, and they destroy the threads. With our bikes, no prob, all thread rod is cheap and easy to replace. Same with welding or brazing, all thread is easy to replace. Most of the issues guys have with the hardware ( that stuff you buy at the hardware store, same stuff that was in the kit, and they just wasted money on, and the guys using hardened stuff risk eating a case thread/s) is they over torque. If the all thread strips before the nut, you are doing it wrong. The nut should always strip out before the bolt,screw, rod. Industry standard. Easier to replace a nut, than a welded on stud, and the bolt, stud, etc is not comprised, holding whatever together still. The nut is expendable, an how it should be.
I run an engine on a rocket fuel mix, studs hold up fine. Thick cast head ain't even stressing.
