SPRING 2020

102 THE DISTRIBUTOR’S

102 THE DISTRIBUTOR’S LINK LAURENCE CLAUS WHY FASTENER STANDARDS ARE SO IMPORTANT from page 8 As society began to urbanize and industrialize this problem became increasingly more acute. In the early 1840’s, Joseph Whitworth, a pioneering British industrial engineer, began investigating fastener problems associated with railroad steam engines. He studied the leading London suppliers of threaded fasteners and discovered that although their product was generally uniform within their own product lines, there was little or no correlation with the neighboring competition. This led Mr. Whitworth to publish, “A Uniform System of Screw Threads”, defining the Whitworth thread form and making history as the first industrial standard. Within several years this 55° angle profile thread would become the British national thread form, accepted throughout Great Britain and the British colonies. About twenty years later, William Sellers, a United States engineer would propose the Seller’s Thread Form. This was different than the Whitworth thread form, primarily in the 60° angle profile of its thread. The Seller’s thread would quickly become the American Standard, adopted in 1868 as the US national standard and as the national standard throughout much of mainland Europe in 1898. Although multiple, competing standards are rarely an ideal situation, this was fine until world war broke out and the United States and British war machines were comingled. Since the British were using the British National (Whitworth) thread and the US were using the American National (Sellers) thread, and the two were not interchangeable, maintenance problems arose immediately. Fortunately for the Allies World War I would resolve itself relatively quickly after first experiencing these problems but rise again to greater heights during World War II. After World War II ended, leaders were committed to not let this problem occur ever again, and so a council was convened and a harmonized screw thread was established, the Unified Thread Series. As more countries adopted the Metric System, a standard for metric threads would need to be developed. The version used today, ISO 68, was developed in the early 1970s. Fastener standards fall into one of five categories; [1] Product (or Dimensional) Standards - these inform the user how to make the part [2] Material Standards - these inform the user on a material or process used to make a part or an operation such as heat treating or plating that may be conducted on a part [3] Testing Standards - often test requirements are included in the Product or Material Standard but occasionally are developed into a stand-alone document informing how the part should be tested [4] Procurement Standards - provide information about requirements the purchaser may have relative to a part [5] System Standards - these are often Quality Management System standards such as ISO 9001 and provide guidance on all aspects of structuring and running one’s business or some sub-system of a business In addition to these five different categories, fastener standards have two types, Consensus Standards and Non-Consensus Standards. Simply defined, a Consensus Standard is derived by a consensus standard organization, or one which employs the principle of open access by industry participants and experts who work together using a structured process that insures consensus of the end product. Organizations like ASTM, ASME, SAE and ISO are all consensus standards organizations. By contrast, a Non-Consensus standard is generated by a non-consensus organization, which means that the input is either not open or there is no process to make sure that the users of the standard agree to the contents. Non-Consensus Standards exist for the sole and exclusive benefit of the entity that creates them. Common examples of Non-Consensus Standards include all automotive OEM standards, MIL Standards, and OEM aircraft manufacturer standards. An important item to clarify at this point is the relationship between Consensus and Non-Consensus standards. One might like to think that there would be no relationship between the two, and occasionally this is true. More often, however, Non-Consensus Standards rely heavily on the Consensus Standards. CONTINUED ON PAGE 148