The letter “J” need not be marked on the tap. Internal UNJ threads are not required to have a root radius therefore, ground-thread taps designed to produce Unified Screw Threads of the proper class of fit may be used. Therefore, some of the tooling used to produce one form can be used to produce the other.Įxternal UNJ threads must be produced with a prescribed root radius therefor, standard Unified Screw Thread (UN) may not be used. Many of the UNJ thread form characteristics are the same as for a UN threads. UNJ product threads are identified by the letter “J” in the thread symbol, and a thread class symbol including an “A” for external threads or a “B” for internal threads. There is no radius requirement for either the crest or the root of the internal thread.ĭesignation. Internal threads: the minor diameter is increased to accommodate the maximum root radius of the external thread. UNJ screw threads are the same form as Unified Screw Threads to ASME/ANSI B1.1 except:Įxternal threads: the root has a maximum and minimum prescribed continuous radius, and is not merely rounded due to tool wear. Due to the increase in both its use and types of applications, the American Society of Mechanical Engineers developed and published ASME B1.15 in 1995.įorm. MIL-S-8879 was primarily thought of an used for aerospace fastener and threaded component applications. It was derived from a military specification (MIL-S-8879) originally published in December 1965. The UNJ thread standard (ASME B1.15) defines a system of threads for highly stressed applications requiring high fatigue strength.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |