M38A1 CDN3 wheel nut question

[BCA]

Thanks to all for their observations. Interestingly the correct nut 5310-00-391-0687 is described as being "self-locking" and having an "all metal locking feature". I suspect the threads are slightly distorted to make them self-locking. The "all metal" feature means they are not to be "Nylock" or other non-metal locking feature. Look carefully at your original wheel nuts and see if you can see a dimpling or punch marks on the flat hole opening that indicate if the threads were distorted. ……….. Brian

[Grant Bowker]

I know the discussion is about M38A1 but another vehicle of the same vintage, my M135, had many self-locking nuts of the type shown below, BUT the wheel nuts were ordinary commercial items (no locking function). I don't recall ever having seen self locking wheel nuts. Maybe I'm not observant enough... Also some of the distorted lock nuts require significantly more torque to run down the bolt/stud compared to a regular nut (and more as they get larger).

[rob love]

When I look up that NSN, it comes up with a number of commercial numbers. Included in that is Kelsey Hayes X1023R, which is a fairly common civilian number. There is nothing self locking about those, aside from perhaps the 60° cone. Perhaps they consider that the locking feature.

The NSN was still valid for certain other equipment in Canada until 2017. The US list it as being for: ENGINE, AIRCRAFT T-64,F117A AIRCRAFT,SHIPBOARDMATERIAL HANDLING EQUIPMENT (MHE), INTEGRATED UNDERWATER SURVIELLANCE SYSTEMSAIRCRAFT, ORION P-3,AIRCRAFT, HAWKEYE E-2C