Here's a dumb question: Since these bolts are such oddballs in the US,
what's to stop people from using a 1/2-20 SAE tap and just installing new
Grade 8 SAE 1/2-20 bolts? Just curious. If that's an insane idea, is there
a source for suitable and appropriate replacement crossmember bolts
anywhere? Thanks. M
On 7/14/10 10:57 AM, "Smit, Theo" <Theo.Smit@dynastream.com> wrote:
> Good question! I re-read the various standards (at least as described by
> Wikipedia) and combined with the Alpine parts reference cited earlier I don't
> think that these are British thread after all.
>
> BSW (British Standard Whitworth) in 1/2" has a 12 thread pitch, while BSF has
> 16 threads per inch. We know that the chassis bolts are 1/2-20. UNF is spec'ed
> at 1/2-20 while UNC is 1/2-13.
>
> So the question that remains is, are these bolts made with a 60 degree thread
> profile or not? If they are, are they designed for an interference fit (which
> might explain why a standard die will remove material from the bolt threads)?
>
> As already stated, these bolts have a longer threaded section and shorter grip
> length (thanks Mayf!) than a standard SAE bolt, so you can't easily go to your
> local ACE hardware store to buy replacements. Using a thread die to put extra
> threads on a store bought bolt is dangerous because it causes stress risers at
> the root of the threads - conventional bolts have the threads rolled into
> them, which essentially forges the threads into the bolt and strengthens the
> threaded area.
>
> Theo
> ________________________________________
> From: tigers-bounces@autox.team.net [tigers-bounces@autox.team.net] On Behalf
> Of Carmods@aol.com [Carmods@aol.com]
> Sent: Tuesday, July 13, 2010 3:07 PM
> To: tigers@autox.team.net
> Subject: [Tigers] Crossmember Installation Headache
>
> Jul 13, 2010 09:52:38 AM, Theo.Smit@dynastream.com wrote:
>
> they're British fine thread which is almost but not quite the same as SAE:
>
>
>
> Theo,
>
> Are you sure those bolts are British Standard Fine Thread (BSF)?
>
> What size are they?
>
> John Logan
> _______________________________________________
>
>
> -----------------------------------------------------------------------------
> ---
> This e-mail and any attachments may contain confidential material for the sole
> use of the intended recipient. If you are not the intended recipient, please
> be aware that any disclosure, copying, distribution or use of this e-mail or
> any attachment is prohibited. If you have received this e-mail in error,
> please contact the sender and delete all copies.
>
> Thank you for your cooperation.
> _______________________________________________
> Tigers@autox.team.net
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/tigers/mcdangerous@verizon.net
_______________________________________________
Tigers@autox.team.net
Donate: http://www.team.net/donate.html
Archive: http://www.team.net/archive
Forums: http://www.team.net/forums
|