ASME B1.7:2006 pdf free download.Screw Threads: Nomenclature, Definitions, and Letter Symbols.
The purpose of this Standard is to establish a uniform practice for standard screw threads with regard to the following:
(a) screw thread nomenclature
(h) letter symbols for the designating features of a screw thread for use on drawings, in tables that set forth dimensional standards, in other records, and For expressing mathematical relationship
This Standard consists of: a glossary of terms, illustrations, an illustrated table showing the application of symbols, and a table of thread series designations. Many of the terms and symbols specified in this Standard vary considerably from those prior to the 1984 issue, because ISO terms and symbols have been adopted where the intended definition is the same.
1.2 References
The following is a list of publications referenced in this Standard.
ANSI/CGA V-i, National Gas Screw Threads’
Publisher: Canadian Gas Association (CGA), 350 Sparks Street, Ottawa, Ontario K1R 7S8, Canada
ASME P1.20.7, Hose Coupling Screw Threads ASME Y14.5M, Dimensioning and Tolerancing
Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, New York, NY 10016-5990; Order Department: 22 Law Drive, P.O. Pox 2300, Fairfield, NJ 07007-2300
ISO 7-1, Pipe Threads Where Pressure Tight Joints are Made on Threads—Part 1: Designation, Dimensions, and Tolerances
ISO 228-1, Pipe Threads Where Pressure Tight Joints are Not Made on the Threads—Part 1: Designation, Dimensions, and Tolerances
ISO 1502, ISO General Purpose Metric Screw Thread- Gauging
ISO 2901, ISO Metric Trapezoidal Screw Threads
ISO 2902, ISO Metric Trapezoidal Screw Threads
ISO 2903, ISO Metric Trapezoidal Screw Threads
150 2904, ISO Metric Trapezoidal Screw Threads
LSO/R1501, ISO Miniature Screw Threads
gage, thread limit gage: used to determine whether a thread is within the maximum or minimum material limit. See also attribute.
gage, thread plug gage: a plug that has an external thread, used as a setting or work gage.
gage, thread ring gage: a ring that has internal threads, used as a setting or work gage.
gage, thread snap gage: a limit gage that utilizes mo’able thread segments or rolls to check a characteristic or attribute of a thread. A snap gage for all external thread engages by passing over the threaded part. A snap gage for an internal thread is placed within the thread and spring loaded contacts release to provide thread engagement.
gaging length: see kngth, gaging.
gauge plane: An ISO taper pipe thread term equivalent to the U.S. term “plane of hand tight engagement, X = 1”. Its location from the reference plane at the small end of the thread is called the gauge length, L, in the U.S., and the major diameter at this plane is called the gauge diameter, D1 in the U.S. (see Fig. 17).
groove diameter: see pitch diameter, thread groove diameter. haIf-anle: see flank angle.
height of flandamental triangle: the height of the fundamental triangle of the thread. The height of a sharp Vthread is the distance measured radially, between the sharp major diameter and sharp minor diameter cylinders or cones respectively (see Fig. 113).
height of thread: the height (or depth) of a thread is the radial distance, measured perpendicular to the thread axis, between the major and minor cylinders or cones respectively (see Fig. 19).
height of thread engagenient: the radial distance, measured perpendicLllar from the crest of the internal to the crest of the external, where the thread forms engage mating threads in an assembly (see Fig. 20).
helical path: see helix variation,
helix: the curve on a cylindrical or conical surface, which intersects all planes perpendicular to the axis, at a constant oblique angle (see Fig. 21). A helix on a cylindrical surface, which has been unrolled (developed), will appear as a series of equidistant straight lines.
helix angle: a complement to the lead angle (see Fig. 21). helix variation: the axial variation of the screw thread’s actual helical path on the pitch cylinder relative to its true helix within the gaging length (see Fig. 22). See also drunken thread or lead.
imperfect thread: see incomplete thread. included angle: see thread angle.
