7/16" x 24 theard bolts

All things K & Sportster

7/16" x 24 theard bolts

Postby belmont » Mon Mar 27, 2023 9:03 pm

I stumbled on some oddball bolts and was wondering if anyone knows what they were made to be used on. They are 7/16-24 thread. Parkerized, plain head. 1/4" thick and 5/8' hex head.

Thanks, belmont
belmont
 
Posts: 2
Joined: Fri Mar 10, 2023 9:28 am

Re: 7/16" x 24 theard bolts

Postby hennesse » Tue Mar 28, 2023 10:52 am

This is an odd thread - finer than fine. This would probably be used in an application that is subject to a lot of vibration.

Here are the 7/16 bolts from the 1959 K/XL Spare Parts Catalog. Note that in this, and most Harley catalogs, the tech writer has capriciously misapplied the N.C. and N.F. labels. 7-16"-14 is National Coarse, and 7-16"-20 is National Fine. Ignore the abbreviations, and use the Threads Per Inch.

Capture.JPG
Note capricious misuse of N.C. and N.F.
Capture.JPG (30.39 KiB) Viewed 36107 times


National Coarse was formerly known as U.S.S. and National Fine as S.A.E.

Harley also uses the N.S. abbreviation for some obsolete threads ("National Special"), of which they use very few. One is 1/4"-24. (1/4"-20 is N.C. 1/4"-28 is N.F.). Bolt 2768 and nut 7691 were used to attach the 1952-1955 taillight to the fender. There are a couple of other instances of this thread. These were standard many years ago, but are long obsolete. But Old Dude still sells them.

Most other weirdo bolts and nuts get a Harley number, and they don't list the specifications.

What do your bolts fit? What's the last piece of antique farm machinery, airplane, industrial pump that you took apart?
User avatar
hennesse
Site Admin
 
Posts: 668
Joined: Sat Mar 29, 2014 11:28 pm
Location: Warrenton, Virginia

Re: 7/16" x 24 theard bolts

Postby Promod117 » Tue Mar 28, 2023 11:32 am

hennesse wrote:This is an odd thread - finer than fine. This would probably be used in an application that is subject to a lot of vibration.

Most other weirdo bolts and nuts get a Harley number, and they don't list the specifications.



Harley started putting the hardware specs in their Dealer Accessory Guide, section 2. Listing is in part number order. Started about 87, I think. I have 4 versions. '87, '94, '13 and an undated copy. If an admin wants to post them in the tech section, I will gladly forward.
Promod117
 
Posts: 38
Joined: Sun Jan 12, 2020 1:41 pm
Location: NE Ohio

Re: 7/16" x 24 theard bolts

Postby belmont » Tue Mar 28, 2023 12:37 pm

hennesse, I have several original parts books going back to 1939 and ending in 2001. Harley put an list of fasteners and their description at the beginning of the index pages at the end of the books starting with the change to the "new" part number system in 1949. They continued that through the 50's, after that the description for them was in the part number list on most every page, and that practice ended in 1980 or 81. Prior to 1949 they rarely had a description for any bolt larger than 3/8' dia. I had acquired these oddballs in an inventory buy out MANY years ago, they were in a bin marked "Misc" full of all kinds and types of obscure bolts and nuts. I am down to less than 10 that I am stumped on their designed use. These are NOS from a Harley dealer that started business in 1939 and never hesitated in buying up obsolete parts when he got the chance over the years. I consider myself lucky in that his parts guy was very thorough in keeping them identified. These were probably given part number with a dash and year of origin number for their unique use. Harley had several unique thread pitch fasteners that were 3/8-24V, for example. I have no way to be sure if these are 24V thread without a microscope to study the thread shape. My hope is that there is someone out there that knows the answer.
belmont
 
Posts: 2
Joined: Fri Mar 10, 2023 9:28 am

Re: 7/16" x 24 theard bolts

Postby panic » Tue Mar 28, 2023 1:01 pm

The other 7/16" bolt is the 7/16-16 NS flathead head bolt (knucklehead, some 45, and 1930-48 VL/UL)
I've seen K cylinders stripped out by using 45 head bolts, they appear to go in, then...
[url="http://victorylibrary.com/L-BK.htm"]The Linkert Book[/url]
User avatar
panic
 
Posts: 132
Joined: Mon Jul 29, 2019 5:33 pm

Re: 7/16" x 24 theard bolts

Postby Magneto Sportster » Tue Mar 28, 2023 4:44 pm

post a photo
Magneto Sportster
 
Posts: 107
Joined: Tue Apr 15, 2014 8:41 pm

Re: 7/16" x 24 theard bolts

Postby Rubone » Tue Mar 28, 2023 7:21 pm

I can do a little research. I have every parts book and supplement printed from the early twenties to the 70s. Like this bunch...
Attachments
DCP_4752 (2).JPG
DCP_4752 (2).JPG (186.8 KiB) Viewed 36009 times
DCP_4762 (2).JPG
DCP_4762 (2).JPG (155.21 KiB) Viewed 36008 times
Rubone
 
Posts: 117
Joined: Thu Oct 26, 2017 6:48 pm

Re: 7/16" x 24 theard bolts

Postby hennesse » Thu Mar 30, 2023 11:04 am

belmont wrote:hennesse, I have several original parts books going back to 1939 and ending in 2001. Harley put an list of fasteners and their description at the beginning of the index pages at the end of the books starting with the change to the "new" part number system in 1949. My hope is that there is someone out there that knows the answer.


Sorry, i just looked in the K and Sportster manuals. Rubone's Library looks like the best place to search. Of course, it may not he Harley at all - I've gotten lots of weird things in boxes of motorcycle parts.
User avatar
hennesse
Site Admin
 
Posts: 668
Joined: Sat Mar 29, 2014 11:28 pm
Location: Warrenton, Virginia


Return to General K / Sportster Discussions

Who is online

Users browsing this forum: No registered users and 16 guests