If I may also interject...you will notice you have tow different types of nuts here. The single nut is a nylon threaded lock nut. It does not require assistance in "staying put." The nylon provides resistance and will not vibrate or move. The other two are standard nuts and in this application are known as lock nuts. One nut is tightened against the other creating pressure on the threads and locking both nuts into position. If you look at the total application, the nylon lock is being used to pull on the bracket which closes the slide. The jam nuts push on the braket to open the slide. The gap in between allows for adjustment if necessary.
Phil