ASME B1-15:1995 pdf download Unified Inch Screw Threads (UNJ Thread Form)
1.1 Scope This Standard establishes the basic triangular pro- file for the UNJ thread form, provides a system of designations, lists the standard series of diameter- pitch combinations for diameters from 0.600 to 6.000 in., and specifies limiting dimensions and tolerances. It specifies the characteristics of the UNJ inch series of threads having 0.1501 1 P to 0.18042P designed ra- dius at the root of the external thread, and also having the minor diameter of the external and internal threads increased above the ASME B 1.1 UN and UNR thread forms to accommodate the external thread maximum root radius.
1.2 Field of Application The UNJ screw thread is designed for aerospace inch threaded parts, or for use on other highly stressed applications requiring high fatigue strength. For aero- space applications, only Classes 3A and 3B should be used.
1.3 Assembly Threads conforming to the UN profile (ASME B1.1) and the UNJ profile are not interchangeable because of possible interference between the UNJ external thread minor diameter and the UN internal thread minor diameter. However, the UNJ internal thread will assemble with the UN external thread.
1.4 Federal Government Use When this Standard is approved by the Department of Defense and federal agencies and is incorporated into FED-STD-H28/4, Screw Thread Standards for Federal Services, Section 4, the use of this Standard by the federal government is subject to all the re- quirements and limitations of FED-STD-H28/4.
1.5 References The latest issues of the following documents form a part of this Standard to the extent specified herein.
American National Standards
ASME B1.1, Unified Inch Screw Threads (UN andUNR Thread Form)
ASME B1.3M, Screw Thread Gaging Systems forDimensional Acceptability
ANSI/ASME B1.7M,Nomenclature, Definitions,and Letter Symbols for Screw Threads
ASME B1.23′, Gages and Gaging for Unified InchJ Series Screw Threads
ASME B1.30M,Screw Threads – Standard Prac-tice for Calculating and Rounding Dimensions
2.1 Basic Profile
The basic profile is the theoretical profile corresponding to the basic dimensions of the thread major diameter, pitch diameter, and minor diameter. Profile applies to an axial plane. The basic profile is shown in Fig. 1.
2.2 Basic Thread Profile Symbols
The symbols used in the basic profile shown in Fig.1 represent the following:
D bsc = basic major diameter of internal thread
D2 bsc = basic pitch diameter of internal thread
Dl bsc = basic minor diameter of internal thread
d bsc = basic major diameter of external thread
d2 bsc = basic pitch diameter of external thread
dl bsc = basic minor diameter of external thread
8 = height of fundamental triangle
P = pitch
ASME B1-15:1995 pdf download
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