[Healeys] 100 fasteners

[Curtis Arndt]

Regarding the steel and strength ratings of British and other fasteners,
they were either *"Mild"* Steel (British grades unmarked or A, B, C or K
for nuts with "B" being the most common after unmarked) or *"High Tensile"*
steel (all other letter grades D-G [pre 1950] and R-Y [post 1950]).  The
confusion appears in calling "*High Tensile Steel*" - "High Speed Steel" as
Michael has pointed out.

See my attached article...

Also with regard to fastener listings in the various parts manuals and
other BMC publications, if a fastener is noted with a "part number", it is
typically a Whitworth type thread form. When the changeover to "Unified "
fasteners occurred in the mid 1950s, all Unified fasteners were noted with
a new designation, describing in code the size of the fastener.  I would
assume that all Unified fasteners fell under this new coding system... But
we know what happens when we assume.

BTW, this Unified fastener coding is published in a chart that most of you
should be familiar with by now.

For those unfamiliar, the "British Standards" define "Whitworth" as all
thread forms with a pitch angle of the threads measuring 55°, e.g., BSW,
BSF, BSPP, BSPT, BSB, etc... This is in contrast to Unified (UNF/UNC), SAE
and BSCy thread forms which have 60° pitch angle of the threads.   This is
why British Standard Cycle are NOT a Whitworth thread form despite the bolt
heads using BSW/BSF spanners, and what is erroneously published in
Wikipedia... But I digress.

That being said, I would assume that part numbers (11B122 and 11B 298) are
both Whitworth fasteners since they are listed as part numbers.  Again, we
all know what happens when we assume! Since these are specialty fasteners,
and not your run of the mill bolts, who knows how BMC designated them? One
may be BSF and the other UNF.  Measure twice or have a Helicoil kit on hand!

Cheers,

Curt

On Thu, Feb 10, 2022 at 4:23 PM Henry G Leach via Healeys <
healeys at autox.team.net> wrote:

> I don't want to be a smart ass, here like Ralph found in "Christmas
> Story", and stick my tongue to a light pole, but the treads found on my
> rocker oil feed pipe are *HSS, 26TPI*. Here are two measurements with a
> gauge showing the pattern. If it was 3/8 x24 UNF the job would be done.
> However, I had to order a special $65 kit for the HSS Helicoils to repair
> this block.
>
> Now, here are our 55 degree choices: *UNF 3/8 x 24*, BSW 3/8 x 16, *BSF
> 3/8 x 20*, HSS 3/8 x26, BSC (old CEI) 3/8 x 26 as well, or BSPF 3/8 x 19.
> Unless someone re-lathed this part it is factory 26TPI for sure-ran a tap
> and die in both parts.
>
> A note in the Sept. 1956 parts book refers to a service change shown here.
> (Vol 25, p.13 engine) The BMC group is trying to standardize this item.
> Accordingly, it appears to have been UNF (11B122) on the 2.2 Diesel engine
> and then changed to BSF (11B 298) at engine #225030. This engine I'm doing
> is from 1953 so who knows what the correct part is?
>
> In my March 1954 parts book the number for the "valve rocker bracket with
> tapped hole" is 1B2110 and  locating pin is 1B2111. (no mention of TPI)
> That changed to 11B298 and 99.(BSF) in 1956. Of course the later 6-cyl.
> engines used AEC162-probably unified, but maybe still BSF.
>
> If someone has the right answer, I will stick my tongue to a light pole.
> Hank
>
> -----------------------------------------
> From: "Michael Salter"
> To: "Bob Haskell"
> Cc: "Bob Spidell", "Hank Leach", "Healeys"
> Sent: Wednesday February 9 2022 10:52:51AM
> Subject: Re: [Healeys] 100 Road draft (vent) pipe fasteners
>
> The fasteners wouldn't be HSS ...that is used for machine tools like drill
> bits and lathe tools.
>
> M
>
> On Wed, Feb 9, 2022 at 1:47 PM Bob Haskell via Healeys <
> healeys at autox.team.net> wrote:
>
>> Bob,
>>
>> HSS - high speed steel.
>> I think the threads are 3/8"-26 BSF (British Standard Fine).
>>
>> Cheers,
>>
>> Bob Haskell
>> Austin Healey 3000 BN7/BT7 registrar
>
>
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