Phil
Caged nuts are available form Spaenaer box of 50, they have a web site! Ontario supplier
http://www.spaenaur.com/
P/N N69 for 1/4-20 NC
P/N N61 for 5/16-18 NC
Used for my CGT restoration, drill both flanges 1/4 inch and plug weld if you can't spot weld. Used well over 50 for cab alone.
Best Regards Walde
west coast BC Canada