User talk:174.20.84.1

Regarding https://en.wikipedia.org/wiki/United_States_Standard_thread
This page, in common with most published histories regarding screw fasteners, skips over a major chunk of the development of threaded fasteners - not only in the US, but world-wide.

It also provides some very erroneous inferences. Namely, it implies that Sellers drew upon material produced by Joseph Whitworth of Britain to create an 'improved' thread design that became the standard for US-made threaded fasteners. While he may actually have done so, this ignores a major part of the threaded fastener development story.

Some forty years earlier, another person had done the same thing. His name was Captain John H. Hall, the designer of the Hall breech-loading rifle. In 1819 Hall obtained a contract with the US War Department to build rifles of his design, but the contract (at his insistence) specified that all the parts of his rifles had to be interchangeable between assemblies. This required uniform fasteners, something that did not exist in that time. In fact, each and every firearm built at the national armories in Springfield Massachusetts and Harpers Ferry Virginia in 1820 had threaded fasteners that were unique to the individual assemblies. Each firearm, when completed, consisted of its assembly parts, a ramrod, the cleaning devices, and a tap and die pair for making new fasteners. Each tap and die pair was unique. There were no high-tolerance standards, only non-standardized eyeball gauges for hand-filing the cutting threads of the taps, which then were hardened. Those were used to make the corresponding dies, before those were hardened. Then each set was used to create the fasteners for a single firearm.

Hall rectified that. Between 1819 and 1822 he designed a standard thread specification, which he submitted to the War Department between a year and two years before Sellers was borne. That standard specification was accepted and used for all Hall firearms. It also was used from then on for all firearms produced for and accepted by the US War Department, making it the first US thread standard and predating Whitworth's more-complex version by some 20 years. In its design and specification, it was indistinguishable from what Sellers presented forty years later, granting that Sellers' specification extended the sizes. In fact, Sellers may have been aware of the earlier Hall specification and simply elaborated on it. In fact, it is entirely possible that Whitworth also may have known about Hall's specification.

One of the main Allied compatibility issues in WWII was that the British Whitworth fasteners used both screws and nuts that had rounded peaks and valleys in the threads. The (by then ASTM) US fasteners had flatted ones. British screws would not fit into US nuts or drilled and threaded holes, making repair of US-made devices difficult. That was why the United Thread specifications came into being.

As a technical publications specialist, I recommend that the text of this Wikipedia Web page be modestly corrected to include an appropriately-placed link in the text to the page

https://en.wikipedia.org/wiki/John_H._Hall_(gunsmith)

about Captain Hall. His contributions not only to fasteners, but also to developing the machines that could reliably produce high-tolerance identical parts, provided the real foundation of developing the art and science of mechanical engineering in this era long before the founding of both the Franklin Institute and ASME. For just one (of many) examples, his design for a straight-cutting machine for making cuts in metal is the basis of today's versatile milling machine. He also developed the first reliable technique for drilling straight bores in steel barrels. He partially case-hardened the barrels before drilling the bore, which forced the drill to follow the path of least resistance - the soft center of the metal bar. As a result, all of his machine-made rifles were twice as accurate as any single one of those that the best, most skilled manual gunsmith in either of the US Armories could make.

There also is an error on the page about Captain Hall. It states:

"These machine-cut surfaces would then be hand filed to ensure fit and interchangeability, verified by a gauging system Hall had designed."

This statement is fundamentally incorrect, and it should revised. It was true of parts for rifles made by Cyrus McCormick, and initially those made by Simeon North, but Hall's whole purpose in his development of his rifle factory was to turn out identical parts from machines that did NOT require hand filing or other redress in order to be interchangeable. In this endeavor he was entirely successful. In the flood of 1852 at Harpers Ferry, storage cases containing 8000 of his rifles were water-damaged. It was necessary to break open the cases, disassemble the rifles, and dry the individual parts in an attempt to salvage some of them. The parts were put in jumbled piles. When reassembled, the superintendent of the Armory was astounded to find that all 8000 rifles were in working order after being reassembled from non-original parts - WITHOUT any hand-fitting!

Please revise the statement to read "These machine-cut parts then were verified by a gauging system Hall designed, to ensure fit and interchangeability."

Also, in the Wikipedia page at:

https://en.wikipedia.org/wiki/United_States_Standard_thread

that text also should be modified. Presently, it states

"William Sellers originally developed the USS thread, and set forth many of its details in his paper, "A System of Screw Threads and Nuts", presented in April 1864 to the Franklin Institute."

That should be revised to read "William Sellers developed the specification for the USS thread, based upon earlier standards developed by Captain John Hall of the US and Joseph Whitworth of Britain. He set forth many of its details in his paper, "A System of Screw Threads and Nuts", presented in April 1864 to the Franklin Institute." That edit should links links to both Hall's and Whitworth's pages.

If I can be of assistance regarding references, please contact me. My mother was the USNPS Harpers Ferry National Monument (now National Historic Site) Historian from 1954 to 1962.

174.20.84.1 (talk) 10:38, 29 January 2021 (UTC)

John L. Fairbairn

Technical Publications Specialist

Rush Creek Research Company

jlf@rcrco.com