Общий каталог Widia 2017 - страница 1805

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Technical Information Inch Screw Thread with UNJ Profile A thread system is available for aerospace and other applications where high fatigue strength is required. The UNJ thread form is defined by ASME B1.15 and is similar to Military Specification MIL-S-8879. Screw thread assemblies consist of external and internal threads. In order to minimise the stress on the external UNJ thread, a controlled root radius is required that is equal to 0.15011P to 0.18042P, where P is the thread pitch. Internal UNJ threads are not required to have a radius at either the major or minor diameters. Nut: UNx/UNJx Screw: UNx UNJx UNx: R0.14434P-0.125P Because external UNJ threads must be produced with a defined For UNJ thread specifications, the reader is referred to ASME B1.15. root radius, standard UN tooling may not be used. However, internal Please note this standard includes Class 3 and Class 2 UNJ screw UNF threads may be produced with ground thread UN taps sized to threads. However, only Class 3 UNJ threads meet the requirements produce the proper class of fit. The tap does not need to be marked of Military Specification MIL-S-8879. For Unified Inch (UN) thread with a letter J. Attention must be paid to the tap drill since the minor specifications, refer to ASME B1.1. diameter has to be specified so as to provide clearance with the root radius on the external thread. widia.com Y101 Technical Information