If the Germans HAD defeated Britain in WWII, they would have gone mad trying to
figure all that out. Maybe that was the plan...
Gordon Glasgow
Renton, WA
> -----Original Message-----
> From: owner-datsun-roadsters@autox.team.net
> [mailto:owner-datsun-roadsters@autox.team.net]On Behalf Of John
> Fernandez, Jr.
> Sent: Monday, April 29, 2002 5:26 PM
> To: datsun-roadsters@autox.team.net
> Subject: Re: front suspension bolts
>
>
> On 29 Apr 2002, at 19:40, Mike Faggart wrote:
>
> > anybody on the list that can tell me what size bolts go where for the front
> > suspension pics from gordon's pages. I have the front susp. in boxes with
> > loose bolts. Yes, I will get new ones to replace the old.
> > HHHHHEEEELLLLLPPPP!!!!
> > looks like I am relearning the alphabet with A bolt, B bolt, C bolt,
> >
> > mike faggart
> > seroc
> Here's a little history of bolts and nuts I got off another car list. I
> know it does not have datsun in it but it will give people some idea
> of all the different and weird sizes of bolts and nuts and why some
> cars have both metric and standard faseners.
>
> John F.
>
>
> History of Whitworth
>
> Although written for a British motorcycle audience, this
> also applys to
> many earlier British cars. It was reproduced on the
> British Cars list
> with
> permission from the author Charles Falco.
>
> A lecture on the meaning of "Whitworth"
>
> First, a tiny bit of history. In the 19th Century every British
> factory
> which needed to bolt something to something else
> devised their own
> fasteners to do it. Clearly, this caused all sorts of
> compatibility
> problems. So, along came Mr. Whitworth (I forget his
> first name right
> now)
> who invented a standardized
> system of coarse threads (with 55 degree thread angle
> and rounded roots
> and
> crests).
>
> This standardization was a Good Thing. Along with his
> threads came heads
> for the bolts that were based on the length *along* the
> side of one
> flat,
> rather than across the flats. Hence, there is no simple
> fractional
> number
> for the length across the flats, which is why your
> American wrenches
> don't
> fit. The fractional number on your English wrenches
> refers to the
> diameter
> of the bolt (which is 1/4", 3/8" etc. just like in the U.S.);
> not to the
> distance across the flats (which ends up being various
> weird
> dimensions).
> Some years later the Brits decided they needed a finer
> pitch for some
> applications, so another thread series was introduced
> (same 55 degrees).
> They also decided that the heads were too big for the
> bolts, so for most
> applications they switched to using the next size smaller
> heads. Because
> of
> this, and to add one more bit of confusion to life, one
> manufacturer
> will
> mark a particular wrench (spanner) "3/8BS," while a
> different
> manufacturer
> will mark the same sized wrench "7/16W." They fit the
> same diameter bolt.
>
> The first thing any fledgling Brit biker learns is that his (or
> her)
> motorcycle has "Whitworth bolts." They think this is
> interesting, buy a
> set
> of "Whitworth wrenches," discover these wrenches fit
> their bolts, and
> believe they now know everything they need to know
> about British
> fasteners.
> Unfortunately, at this point they know only enough to
> make themselves
> dangerous. Instead, what they *should* have said to
> themselves is
> "Ohmygod,
> what other weird and incomprehensible things have the
> Brits done to the
> fasteners on my machine?" The answer to this question
> is:
>
> British Standard Whitworth (BSW)
>
> These are the original, 19th Century, coarse-threaded
> industrial bolts
> designed to hold locomotives together. Because of their
> coarse pitch,
> they
> are more prone to vibrating loose, so are little used on
> motorcycles.
> _Except_ for threading into Aluminum (e.g. crankcase
> studs), where a
> coarse
> thread is
> less prone to stripping than a fine one. It turns out that,
> except for
> 1/2"
> (where the Brits use 12 tpi, and the Americans 13 tpi)
> the thread
> pitches
> are the same as for American Unified Coarse (UNC).
> However, the thread
> *form* is different; Whitworth = 55 degrees; UNC = 60
> degrees. In spite
> of
> this, mismatched nuts and bolts mate nicely, so you're
> likely to find
> UNC
> bolts or studs where BSW should have been.
>
> British Standard Fine (BSF)
>
> A finer pitch series, analogous to the American Unified
> Fine (UNF),
> although--unlike the case of BSW/UNC--with none of the
> pitches in common
> with UNF. Many motorcycle manufacturers commonly
> used a lot of BSF
> threads.
>
> CEI (Cycle Engineers' Institute) or BSC (British
> Standard Cycle)
>
> -these are different names commonly used for the same
> threads.
>
> 60 degree thread angle, rather than the 55 degree of
> BSW and BSF. For
> sizes
> from 1/4" through 1/2" by far the most common are 26
> tpi, although 24
> tpi
> appear as well. *Most*, but by no means all, fasteners on
> post-War BSA's
> (through the late '60's, when it got more complicated)
> were CEI.
> Although
> the thread form and pitch is different, the head sizes on
> CEI-threaded
> fasteners use the same wrenches as BSW/BSF.
>
> British Association (BA)
>
> 47-1/2 degree thread angle. This is a metric thread
> system devised by
> the
> British for small screws used in components like
> speedos. Not metric
> like
> you might expect, but with diameters determined by a
> factor proportional
> to
> a power of the logarithm to the base 10 of the thread
> pitch in
> millimeters.
> I couldn't possibly be making this up. Ah, the English.
> You'll find lots
> of
> BA threads on any British bike, but only for fasteners
> smaller than
> 1/4".
> BA fasteners have their own set of wrench sizes.
> Typically, a set of
> "Whitworth" sockets will include a 0BA (and maybe a
> 2BA--bigger number =
> smaller size) socket.
>
> British Standard Pipe (BSP)
>
> A tapered, self-sealing thread system used to seal fluids
> (interestingly,
> the US *and* the metric world standardized on the BSP system for
> threading
> all their pipes).
>
> UNF and UNC
>
> In the late 1960's, when even the U.S. was thinking of going metric, the
> giant BSA corporation decided it was finally time to scrap that old 19th
> Century Whitworth-based system, and switch to....yes, you guessed it,
> American. Since they had lots of money invested in tooling, the switch
> wasn't made suddenly
> (or completely), so bikes from the late '60's and later had a mix of all
> sorts of thread forms. Typically, engine internals (e.g. the thread on
> the
> end of a camshaft) stayed with whatever form it used to have, while
> simple
> fasteners (e.g. holding the fenders on) switched to UNF.
>
> "None of the Above"
>
> While the above systems account for well over 95% of all threads you'll
> ever run across on a British bike, some manufacturers--again BSA springs
> to
> mind, but others were guilty as well--couldn't restrain themselves from
> inventing a few oddball pitches of their own. This is why, when dealing
> with British bikes, you should assume nothing. You must have a pitch
> gauge
> and calipers.
>
> So, let's get back to the question someone asked a few days ago about
> buying a set of "Whitworth" taps and dies to last him the rest of his
> Brit
> biking life. The first thing I'd say is that if you wants it to last, be
> sure you buy a HSS set (rather than carbon steel), even though it will
> be
> at least 2x the price. Then, in order of overall usefulness, I believe
> you'll find in first place it will be a CEI set, then BSF, then BA.
> Unless/until you really get deeply involved, make do with UNC to
> "simulate"
> BSW (although you'll want to buy an individual 1/2"-12 at
> some point to
> supplement the UNC set). Thus, if you follow my
> recommendation, the very
> *last* thing you'll want to buy for working on your British
> motorcycle is
> a
> "Whitworth" set (I have one, by the way, but only got it
> after I'd had
> CEI,
> BSF etc. for a long time).
>
> Charles Falco
>
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