ALL NUTS ARE NOT CREATED EQUAL!
I tightened mine several times.
I then got close to 4 foot pounds and I could feel the threads giving.
Can't beat a nylock nut.
Also in a real pinch you can smack that nut 1 time with a hammer on appx a 30* angle.
It will deform the nut and it will start fine then get tight about half way.
Some non Nylon lock nuts are actually made that way