Shown on this page are styles of reproduction Model A Ford wheel stud (lug) nuts to watch out for.
Green is good! Red is bad!
Though the nut shown above has the correct stud shoulder relief (green), the minor diameter of the threaded portion of this nut (red) was made too large for the 1/2-20 stud size.
What this means is that the nut will still screw on the stud okay, but the amount of surface engagement between the remaining nut thread and a good wheel stud is greatly reduced and weakened.
Original Ford style wheel studs are swaged into the drum and hub assembly, and have an unthreaded shoulder at their base.
Shown above is another common lug nut problem which adversely affects both the studs and the wheel attachment.
The original design lug nut on the left has the correct corresponding relief in the threads (green) to clear the unthreaded shoulder at the base of the stud.
The low quality reproduction nut on the right has the nut threads running all the way to the base of the nut and has no relief (red) for the stud shoulder.
The only thing the conical wheel nut washers really do is add more mis-fitting interfaces into the joint, as well as wasting valuable thread engagement length of the already-short stud.
The conical washers make a bad situation much worse. I do not care to ride in any car with conical washers on the wheels.
If conical washers are being used to try to compensate for wallowed-out lug nut holes on any wheel, then that is another big red warning flag!
Seriously?? Combining dangerous/damaged wheel(s) with 20 dangerous wheel stud nut and washer attachments??
Grow up and get a good replacement wheel ASAP! Plenty of nice original wheels are out there and available for people intelligent enough to seek and find them. (I myself have about three dozen excellent spare 19" wheels).
Get a set of the correct wheel stud nuts. Then throw away all the foolish conical washers and bad lug nuts!