ASME B1.15:1995 pdf download UNIFIED INCH SCREW THREADS (UNJ THREAD FORM) SECTION 1 GENERAL
1.1 Scope
This Standard establishes the basic triangular pro-file for the UNJ thread form, provides a system ofdesignations, lists the standard series of diameter-pitch combinations for diameters from 0.060 to 6.000in., and specifies limiting dimensions and tolerances.It specifies the characteristics of the UNJinch seriesof threads having 0.15011P to 0.18042P designed radius at the root of the external thread, and also havingthe minor diameter of the external and internal threadsincreased above the ASME B1.1UN and UNR threadforms to accommodate the external thread maximumroot radius.
1.2 Field of Application
The UNJ screw thread is designed for aerospaceinch threaded parts, or for use on other highly stressedapplications requiring high fatigue strength, For aero-space applications, only Classes 3A and 3B should beused.
1.3 Assembly
Threads conforming to theUN profile(ASME B1.1)and the UNJ profile are not interchangeable becauseof possible interference between the UNJ externalthread minor diameter and the UN internal threadminor diameter.However, the UNJ internal threadwill assemble with the UN external thread.
1.4 Federal Government Use
When this Standard is approved by the Departmentof Defense and federal agencies and is incorporatedinto FED-STD-H28/4，Screw Thread Standards forFederal Services,Section 4, the use of this Standardby 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 forma 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 Practice for Calculating and Rounding Dimensions
2.1 Basic Profile
The basic profile is the theoretical profile corre-sponding to the basic dimensions of the thread majordiameter,pitch diameter, and minor diameter Profileapplies to an axial plane. The basic profile is shownin 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 threadD2 bsc = basic pitch diameter of internal threadD, bsc = basic minor diameter of internal threadd bsc = basic major diameter of external threadd, bsc = basic pitch diameter of external threadd, bsc = basic minor diameter of external threadH = height of fundamental triangle
P = pitch
Appendix A provides a complete list of symbolsapplicable to the UNJ thread form.
2.3 Design Profiles
The design profile for the internal thread at max-imum-material conditions is the same as the basicprofile, except in practice, the root is cleared abovethe basic major diameter, D bsc. See Fig.2.The design profile for the external thread at max-imum-material condition for Class 3A is the basicprofile with a radiused minor diameter tangent to the
ASME B1.15:1995 pdf download
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