I baught a set for 100 bucks, 50 a side, no tax at the OFFROAD EXPO in Pomona Ca. in October for my D60. I have to say thay are AWESOME. YES thay are a real simple idea. if you see them in person and how they work and the quality of them, you will be sold.
Im still working on my axle, it is not together yet but I am happy I baught them, especially since I got what I think is a great deal. there clain to fame is over 20 years in bussiness and NO failures. these exact lock nuts are factory on huge Catipiler earth moving equipment, just ALOT bigger. thats where they were developed from, then they thought why dont we make them for smaller axles too. the guys at the show were way cool and talked to me for a long time. I am a machinist so I know what to ask, the whys and hows and what not.
I have 100% faith in these lock nuts. there thicker, made of better materials, maintains proper bearing preload and phisically can not back out once there installed. thay work like an Indexer. thay have like 1 deg increments so all the lock tangs engage, you just have to keep trying to engage it till you find the right point where it engages. it takes like 20 seconds, actually less I bet. Then a snap ring clip is installed. Not like the factory one where you have a couple of tangs that you have to bend over the nut flats.
The piece that keys into the spindle key way is .25 thick, the factory keyway locking washer is like .062. it wont damage the spindle like the factory one will from being worn. A standard 4x4 spindle nut socket works just like on a factory nut. Thay put 8 flats instead of 4 just for added slots to use.
Its all heat treated and hardened for strength.
In the pic above look at the part in the upper right, look at how thay machine the ID tang with radius's leading into the tang. Radius's add strength, the factory stamped sheet metal lock washer has sharp corners at the tang, it starts to tear there usually or if the tang gets worn it wedghes into the threadsbecause the ID of the washer is sometimes loose. thay hold a good tollerence over the spindle diameter to minmize slop. that part is 1/4 in thick and is hardened, it wont wear.