The User Guide for Microphone Drum Mount A56D doesn't show where to install Lock Nuts 31A1857 and 31B1770. Where do they go?
The lock nuts are used on the threaded portion - printed on the side of this portion is "Shure A56D". The lock nut is used to position/lock the plastic mic holder that is threaded onto the A56D.
For example, the Shure SM57 is supplied with a plastic mic holder that screws onto a mic stand or onto the A56D.