imfinlay

Hi all, I'm hoping the assembled knowledge can help me!

I'm restoring a '57 Plymouth, and need to replace some bolts that hold various panels on. They are basically a pointed bolt which goes into a captive nut. They look something like the ones in this ebay auction:

http://snipurl.com/bolt_thingy

Thing is, I don't understand the spec. They're shown as 5/16-18 x 13/16" and I have no idea what this means. I guess that 13/16 is the length and the shaft width is 5/16 with 18TPI thread (which I suppose is UNF?) but I need to be sure so I can measure the one original one I have to then purchase some more!

So, all help appreciated.

Cheers,

Ian
'89 S4 Auto

marton

you want to know about threads? Try
http://www.gewinde-normen.de/en/index.html

Marton

imfinlay

Thanks Marton - I found similar info on wikipedia, but it's just the notation of the vendor I don't understand.

WICruiser

The 5/16 is the nominal bolt size (major thread diameter), the 18 is the threads per inch, and 13/16 is the overall length from the tip to the underside of the head.

imfinlay

Thanks! That's the info I needed!

Ian

Alan

Ahh - of course its a Sunday.. you have a while before Randy's up...

Then

Still seem you got the answer - there are also lots of other web resources on this topic.

Alan

inactiveuser92616

If you care to know the real nitty-gritty on fasteners, PM me and I will dig up a link to a NASA tech paper.

imfinlay

No, really, thanks! I just need to be able to order some replacements for my car!