The UN threadform designator was selected as the first two letters of the word UNified. The Unified threadform was developed jointly by the governments of Canada, Great Britain, and the U S A to be an INTERNATIONAL standard that would overcome the logistical problems encountered during World War II created by the non-interchangeability of the U S and British standard threadforms.
Interestingly, ten years after the Unified threadform was introduced, its basic geometry of the Unified threadform was adopted by the International Standards Organation (ISO) as the ISO Metric threadform. Naturally, the Diameters and Pitches of the ISO Metric threads are dimensioned in millimeters rather than inches.
Some decades later, the ISO accepted the Unified threadform as an ISO Standard threadform, under the name ISO Inch.
It's true that many textbooks and other supposedly-reliable references say that the anti-acronym of the UN threadform designation is Unified National, but the originators of the threadform were specific that their intent was replace national-standard threadforms with one Unified international threadform.
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Today's Featured Article - Hydraulics - Cylinder Anatomy - by Curtis von Fange. Let’s make one more addition to our series on hydraulics. I’ve noticed a few questions in the comment section that could pertain to hydraulic cylinders so I thought we could take a short look at this real workhorse of the circuit. Cylinders are the reason for the hydraulic circuit. They take the fluid power delivered from the pump and magically change it into mechanical power. There are many types of cylinders that one might run across on a farm scenario. Each one could take a chapter in
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