>
> I think my Dad's XK120 (post war) used Whitworth. Steve? You had
> one, is this true.
>
> JC
>
>
> ______________________________ Reply Separator
>_________________________________
> Subject: Re: Crossmember Bolt Tech Tip
> Author: cobra-at-cdc (cobra@cdc.hp.com) at HP-ColSprings,shargw5
> Date: 2/11/98 9:23 AM
>
>
> >
> > BTW, are the stock bolts really 1/2 x 20TPI? The same guy who suggested
> > that grade8 had lower shear strength than grade5 also suggested that the
> > stock crossmember bolts were Whitworth. At this point I think that
> > information is also suspect. But, I ran a 1/2 X 20TPI tap down one of the
> > holes to clean out all the gunk and afterwords it seemed like the stock
> > bolts fit slightly looser than a new 1/2 X 20TPI bolt I had laying around.
> > Thought I'd ask before running the tap down the other three holes.
>
> Not likely Whitworth. Whitworth fasteners were used mostly pre war,
> though some can be found on just post war cars- my old MG TD had more
> than a few. One possibility is BSF, but 1/2 BSF has 16 threads/in
> (Whitworth has 12/in). If you should find some BSF threads somewhere,
> don't rush to clean them up with an SAE tap or die. The threads are cut
> differently and you could end up with a sloppy fit. In case you're
> wondering why I know all this crap, it's 'cuz Cobras have lots of BSF
> fasteners.
Yup, could be. My TD was a '51, the same era as the 120, but very few
Whitworth fasteners got into Brit cars after this time. Also a lot of
people confuse Whitworth with other pre metric British fasteners because
the wrenches fit them. BSW and BSF wrenches were marked differently,
but had the same dimensions. BSF replaced Whitworth in applications
where a finer thread was required and a later coarse thread standard was
adopted which replaced Whitworth. There's a pretty good write-up on
this you can download from the team.net web site if you are interested.
I think I did read somewhere once that Whitworth did continue into the
'60s on parts like lever shocks.
Roland
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