Hard-to-Find Fastener 014973313531 Post w/Screws, 5/16 x 1-1/2, Piece-8

The majority of these Chicago Bolts are available in metric sizes. Why would you need a 5/16-inch bolt and nut when everything works together? 13mm is the metric equivalent of 18 size. However, if you're looking for that specific size, you could try retaping the nut with American sizes. The difference between metric and American threads is that metric threads have a 55-degree angle, whereas American threads have a 60-degree angle. Despite the fact that metric uses millimeters and American uses inches or fractions of an inch, the number of threads per inch should be roughly the same. I switched to metric because it's easier to find...which isn't the case with some of the American hardware used in these proprietary bolts. I'd get one and see if it can be retaped to see if it's usable. I hope you found this information useful.

Yes, each order will include eight pieces.

The shaft is 5/16 inches in diameter, and the screw is 1/4 inch in diameter.