для заказа - kyocera@kyocera-tools.ru UNJ PROFILE
TAPS ENGINEERING DATA
INCH SCREW THREADS - UNJ PROFILE
Controlled Root Radius with Increased Minor Diameter
The UNJ thread standard (ASME B1.15) defines a system Designation. UNJ product threads are identified by the DRILLS
of threads for highly stressed applications requiring letter “J” in the thread symbol, and a thread class symbol
high fatigue strength. It was derived from a military including an “A” for external threads or a “B” for internal END MILLS
specification (MIL-S-8879). MIL-S-8879 was primarily threads.
thought of and used for aerospace fastener and threaded ROUTERS
component applications. Due to the increase in both its Use of Unified Tooling. Many of the UNJ thread
use and types of applications, the American Society of form characteristics are the same as for UN threads.
Mechanical Engineers developed and published ASME Therefore, some of the tooling used to produce one form
B1.15 in 1995. can be used to produce the other.
Form. UNJ screw threads are of the same form as External UNJ threads must be produced with a THREAD MILLS
Unified Screw Threads to ASME/ANSI B1.1 except: prescribed root radius; therefore, standard Unified Screw & TAPS
Thread (UN) tooling may not be used.
External threads: the root has a maximum and ENGRAVERS
minimum prescribed continuous radius, and is not Internal UNJ threads are not required to have a
merely rounded due to tool wear. root radius; therefore, ground thread taps designed to
produce Unified Screw Threads of the proper class of
Internal threads: the minor diameter is increased to fit may be used. The letter “J” need not be marked on
accommodate the maximum root radius of the external the tap. The larger product minor diameter of the UNJ
thread. There is no radius requirement for either the crest internal thread requires the use of a larger tap drill than is
or the root of the internal thread. used when producing Unified Screw Threads.
• UNJ Thread Form: UNJ INTERNAL THREAD BORING BARS
Unified Thread Series
with a 0.15011P to ROOT TO CLEAR 0.125P WIDTH-FLAT OR ROUNDED
0.18042P controlled Assembles with all UN External Threads
root radius on external
thread only. (As defined REAMERS
by MIL-S-8879C)
0.5625H
• UNJ internal threads do
not require radius; only 0.125P
external thread requires
radius on root. 0.3125P SAWS
• UNJ external thread UNJ CLASSES 3B AND 3BG 0.3125P
assembles only with No Radius Required on R. 0.18042P
UNJ internal thread. Internal Threads R. 0.15011P TECHNICAL
0.125P
• UNJ tap is standard 2B
or 3B class of fit. 0.6667H
INDEX
UNJ EXTERNAL THREAD
Assembles Only with UNJ Internal
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