1940 Packard info needed

On a 1940 120 Convertible the top assembly and rear bow irons pivot on a large shoulder bolt that threads into a casting in the body. We need to make a pair of these bolts. We have photos and basic measurements but we need to know what thread they are. They look like 1/2 fine or possibly 9/16 ? Thanks in advance to anyone who can help.

I assume your body identification number is 1499.

Look at the lower RH box in the attached photo of my parts manual.

Are you fabricating 31.059?

If so, the part number is 363001.

I do not have any more information or drawings of the part.

Hope this helps somewhat in your quest.

Good luck,

Tom

Thanks, problem solved. They are 7/16 x 20 tpi.