George,
What size allen wrench fits the bolt? That'll often be a clue about what it is. Whitworth fasteners tend to fit SAE wrench sizes.
1972 is pretty late to be specifying a Whitworth fastener, but I wouldn't put it past them. The UK automotive and motorcycle industries had pretty much moved on in the late 1960s. You can actually see the difference in the threads if you look closely...55-degree thread angles (vs. 60-degree) and rounded at the root of the threads (maybe you have to be a mechanical engineer to see these differences).
If it's Whitworth, you have a couple of options. The safe one is to track down a shop in your area that does work on old British cars or motorcycles...they'll have a stash of Whitworth fasteners that they'll likely let you rifle through to get what you need. I'm sure the bolt will have some common equivalent...like a BSA timing cover bolt, or an MG mumble attachment thingy. A couple of phone calls and some greasy paws from sorting through a box of old bolts and you'll be fixed up. If it's not obvious what shop to try, track down a member of a local British car club and ask them (there's a Sterling British Car Club in Lexington).
Your next alternative to to alter the threads to take something more modern. What the frame appears to want is a Whitworth 1/4-20, given your description of major diameter (just under a quarter) and pitch (an M8 is 1.25 pitch, and the Whitworth 1/4-20, which you say has similar pitch, would be 1.27). The simple thing to do is to go to a well-stocked hardware store and buy a 1/4-20 *bottoming* tap and run it in the binder hole (bottoming taps are used to cut threads in blind holes like this). Pick up a 1/4-20 socket head cap screw in a material you like, cut or grind it to length, if necessary, and you're all set.
Altering the threads even more, to take an even bigger metric or SAE bolt is another option, but doesn't sound like it is necessary yet. That would require modification of the head of the replacement bolt.
Let us know how it goes.
Scott
-----Original Message----- From: classicrendezvous-bounces@bikelist.org [mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of James G Allen Sent: Saturday, December 24, 2005 6:08 AM To: classicrendezvous@bikelist.org Subject: RE: [CR]need 1972 Raleigh Pro seat binder bolt
Scott,
The bolt threads into integral threads on the other ear of the binder. Thus, there is no fastener, it is a one piece unit. The Allen head portion is a larger diameter and fit flush in the un-threaded ear. The threaded end then threads into the integral thread on the other ear. Some list-member have suggested it may be a Whitworth fastener. (thanks Brian and Phil)
Thanks,
George Allen Lexington, Ky
At 02:13 PM 12/23/2005, Scott Minneman wrote:
>Can you remove the fastener and show us a photo of what you're after?
>From the description you've given, it would seem like it's simply an M6
>socket head cap screw, which you should be able to easily source at the
>appropriate length (or I could send you one in stainless at any length
>you desire, from my stash here). Perhaps, though, there is something
>special about the fastener you want that's escaping detection/description.
>
>Cheers,
>
>Scott
>
>-----Original Message-----
>From: classicrendezvous-bounces@bikelist.org
>[mailto:classicrendezvous-bounces@bikelist.org] On Behalf Of James G
>Allen
>Sent: Friday, December 23, 2005 7:52 AM
>To: classicrendezvous@bikelist.org
>Subject: [CR]need 1972 Raleigh Pro seat binder bolt
>
>Perhaps this may help. I found a better picture of the seat cluster area.
>
>http://mysite.verizon.net/res87bwz/BikePics/RaleighPro/Seat_cluster.jpg
>
>
>
>
>Season's Greetings list members,
>
>Perhaps someone can make my Holiday brighter. I am in need of a seat
>binder bolt for a 1972 Raleigh Pro. The images on the links don't show
>the seat binder area well but it's the best I can find right now.
>Specifically look at the 1970/71 and 1972 Pro's on the second link.
>According to my calipers, I should be looking for an Allen-head bolt
>about 24 mm long. The non-threaded head should have a diameter of 9.25 mm
and length of 6.45 mm.
>The major diameter of the threaded portion is 5.8 mm and seems to have
>the same threads as the 8 mm Campy seat binder bolt. I've got a lot of
>stuff to trade or am willing to buy outright. Thanks in advance and may
>your Holidays be full of peace and cheer.
>
>George Allen
>Lexington, Ky
>
>
>
>http://www.retroraleighs.com/catalogs/Raleigh-Catalog-1973.pdf
>
>http://www.retroraleighs.com/professional.html