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Cap Nut on H4 SU Lid Size?

Hello Patton,
it is a Whitworth size, 1\4" BSW, very often confusingly marked as 5\16" BSF - 1\4" BSW. I don't know if they will be easy to find in America but they are still available in the UK.

Alec
 
Hi Patton, Alec'S response is probably correct. However, a 14mm socket will work but is a sloppy fit. To obtain the correct sized tool contact; British Tool Co. here in the US at: britool51@Hotmail.Com-FWIW---Keoke
 
Hi Patton,

The 1/4" for a Whitworth bolt is the thread diameter not the across flats size. I don't know how the across flat size was determined.

Mike
 
Brooks/Patton the Cap size is most likely 5/16 BSF. and has an across the flats dimension of;0.525-Keoke
 
Hello all,
yes, Whitworth threads are the bolt diameter, and the confusion between 5\16" BSF and 1\4" BSW as they are the same spanner size is that during the war, to save metal, all British Standard Fine head sizes were reduced to the next smallest size, i.e. a 5\16" BSF bolt or nut had a head size of a 1\4" BSW bolt or nut. The thread form is identical but W is coarser than F. I think I am right in saying that Charles Whitworth, a Manchester (UK) engineer invented the standardisation of fasteners for the benefit of the manufacturing industries.

regards,
Alec
 
Almost - in fact he was Joseph Whitworth, and ranks as one of the all time great Engineers. As you say standardising fasteners was one of his great achievements.

(The cap nuts of my HD8's are 0.810 A/F or 7/16 Whitworth)


"Sir Joseph Whitworth
(1803-1887)
Born in Stockport in 1803, Sir Joseph Whitworth was a celebrated philanthropist and engineer, whose name is remembered throughout Manchester in many street names, an art gallery and a park. His father, a schoolmaster, educated him at home until he was 12, at which time he was sent to William Vint's Academy near Leeds. By the age of 14, Joseph was working in his uncle's cotton mill in Derbyshire, demonstrating an adaptive and inquisitive mind, and a thorough understanding of all the machines used in cotton production.
At 18 years he determined to become an engineer, and he joined a firm of machine makers in Manchester. Here he learned precision and the need for mechanical standardisation, so that when in 1833 he was in a position to set up his own business, he had all the expertise he needed to become a successful businessman. His first workshop was in Chorlton Street, Manchester, and was to be the forerunner of his later great Whitworth Works in Openshaw.
His engineering skill enabled him to produce many mechanical innovations, and his reputation soon grew world-wide. At a time when accuracy was to the nearest sixteenth of an inch, Whitworth developed a technology where on-thousandth of an inch was his acceptable tolerance.
His greatest abiding gift to engineering was the standardisation of sizes and threads in machine screws - the "Whitworth Thread" reigned supreme in metal crafts until the introduction of metrication in the 1970s and 80s. He was also involved in weapon production. The War Office paid for a shooting gallery to be built in the grounds of his home, The Firs, in Fallowfield, so that he could work on improving the accuracy of rifles.
His rifles were so improved that Napoleon III of France awarded Whitworth the Legion of Honour. A strong believer in the value of education, he backed the new Mechanics' Institute in Manchester, and helped found the Manchester School of Design. By 1868 he was donating upwards of ÂŁ3,000 a year towards scholarships and the training of young men in mechanical engineering. On his death he left ÂŁ100,000 to continue the scholarships, as well as another ÂŁ500,00 to other Manchester educational establishments and charitable institutions.
In 1896 he was knighted and received the Albert Gold Medal of the Society of Arts for his pioneering inventions and improved processes in engineering. "
 
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Hello Andrew,
thank you for the correction, my memory let me down a little there.

regards,
Alec

[/ QUOTE ]

Yes Alec, sorry to be pedantic, but he's one of my 'heros' along with Ismbard Kingdom Brunel and Fred Dibnah /ubbthreads/images/graemlins/savewave.gif

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Hello Andrew,
good choices; I wonder what our non UK board members would make of Fred Dibnah?. The original series were particularly entertainig.

Alec
 
You need a Whitworth wrench for the lid nut and the steering box adjusting nut(not the same size). Two kind of obscure places where it really helps to have the proper fitting wrench.
 
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