Personally, I think AICC should be punted over the goal post of so long compliance standards. and some vendors like to offer multiple choices, and yes AICC does different things, but so does driving a moped and I rarely seen people cruising down the interstate on one (unless you live in LA).
Part One: How to Measure Thread Size. 1  In general, the thread should match the fabric in size and weight. For heavier, thicker fabrics, use heavier thread. 2  Heavier threads create more visible stitches. 3  V-69 is the heaviest size recommended for sewing machines. 4  Heavier threads are stronger.
Measuring for Diameter. Lay the nut down as you did in Section 1. Set the end of the tape measure at one side of the inner threads of the nut. Stretch the tape measure to the other side of the inner threads of the nut.Count the lines to find the diameter of the threaded hole. Measure across the widest opening the threads make. This measurement will help you match the thread diameter of the nut with the thread diameter of the bolt.et the end of the tape measure at one side of the inner threads of the nut. Stretch the tape measure to the other side of the inner threads of the nut. Count the lines to find the diameter of the threaded hole. Measure across the widest opening the threads make.