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The Unified Thread Standard (UTS) defines a standard thread form and series – along with allowances, tolerances, and designations – for screw threads commonly used in the United States and Canada. It has the same 60° profile as the ISO metric screw thread used in the rest of the world, but the characteristic dimensions of each UTS thread (outer diameter and pitch) were chosen as an inch fraction rather than a round millimeter value. The UTS is currently controlled by ASME/ANSI in the United States. Standardization, in the context related to technologies and industries, is the process of establishing a technical standard among competing entities in a market, where this will bring benefits without hurting competition. ...
Screw thread, used to convert torque into the linear force in the flood gate. ...
The metric ISO screw threads are the world-wide most commonly used type of general-purpose screw thread. ...
An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...
A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ...
The American Society of Mechanical Engineers (ASME) is a professional body, specifically an engineering society, focused on mechanical engineering. ...
The American National Standards Institute (ANSI) is a private, non-profit standards organization that produces industrial standards in the United States. ...
Origins
The standard was originally adopted by the Screw Thread Standardization Committees of Canada, the United Kingdom, and the United States on November 18, 1949 in Washington, D.C., and applied to screw threads used in the above countries with the hope they would be adopted universally. The standard was not widely taken up in the UK, who continued to use their own BA (British Association) standard and then migrated to ISO metric screw threads. The original UTS standard may be found in ASA (now ANSI) publication, Vol. 1, 1949. November 18 is the 322nd day of the year (323rd in leap years) in the Gregorian calendar. ...
1949 (MCMXLIX) was a common year starting on Saturday (the link is to a full 1949 calendar). ...
Nickname: Motto: Justitia Omnibus (Justice for All) Location of Washington, D.C., in relation to the states Maryland and Virginia Coordinates: Country United States Federal District District of Columbia Government - Mayor Adrian M. Fenty (D) - City Council Chairperson: Vincent C. Gray (D) Ward 1: Jim Graham (D) Ward 2: Jack...
The British Association or the British Association for the Advancement of Science or the BA is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating intercourse between scientific workers. ...
The metric ISO screw threads are the world-wide most commonly used type of general-purpose screw thread. ...
The American National Standards Institute or ANSI (pronounced an-see) is a nonprofit organization that oversees the development of standards for products, services, processes and systems in the United States. ...
UTS consists of Unified Coarse (UNC), Unified Fine (UNF), Unified Extra Fine (UNEF) and Unified Special (UNS).
The International Organization for Standardization's ISO metric screw thread preferred series, based on round millimeter dimensions, is the standard that has been adopted world-wide and has displaced all former standards, including UTS. In the USA, where UTS is still prevalent, over 40% of products contain ISO metric screw threads. Of the above mentioned countries, the UK has completely abandoned its commitment to UTS in favour of the ISO metric threads, and Canada is in between. This article or section does not cite any references or sources. ...
The metric ISO screw threads are the world-wide most commonly used type of general-purpose screw thread. ...
The metric ISO screw threads are the world-wide most commonly used type of general-purpose screw thread. ...
Technical information
Form and pitch UTS thread form and pitch technical specifications are currently controlled by ASME/ANSI industry standards in the United States: - ASME/ANSI B1.1 - 2003 Unified Inch Screw Threads, UN & UNR Thread Form
- ASME/ANSI B1.10M - 2004 Unified Miniature Screw Threads
- ASME/ANSI B1.15 - 1995 Unified Inch Screw Threads, UNJ Thread Form
P = 1 / TeethPerInch
H = 0.866025 * P
H1 = 0.541266 * P
d1 = d + 1.082532 * P
d2 = d + 0.433013 * P
D = d
D1 = d1
D2 = d2 A diagram of a Unified Standard Thread I, the creator of this image, hereby release it into the public domain. ...
Gauging A screw thread gauging system comprises a list of screw thread characteristics that must be inspected to establish the dimensional acceptability of the screw threads on a threaded product and the gauge(s) which shall be used when inspecting those characteristics.
Currently this gauging UTS is controlled by:
- ASME/ANSI B1.2-1983 Gauges And Gauging For Unified Inch Screw Threads
- ASME/ANSI B1.3M-1992 Screw Thread Gauging Systems Dimensional Acceptability Inch Metric Screw Threads
These Standards provide essential specifications and dimensions for the gauges used on Unified inch screw threads (UN, UNR, UNJ thread form)on externally and internally threaded products. It also covers the specifications and dimensions for the thread gauges and measuring equipment. The basic purpose and use of each gauge are also described. It also establishes the criteria for screw thread acceptance when a gauging system is used.
Class of thread A classification system exists for ease of manufacture and interchangeability of fabricated threaded items. Most (but certainly not all) threaded items are made to a classification standard called the Unified Screw Thread Standard Series. This system is analogous to the fits used with assembled parts.
Classes 1A, 2A, 3A apply to external threads; Classes 1B, 2B, 3B apply to internal threads.
Class 1 threads are loosely fitting threads intended for ease of assembly or use in a dirty environment.
Class 2 threads are the most common. They are designed to maximize strength considering typical machine shop capability and machine practice.
Class 3 threads are used for closer tolerances.
Thread class refers to the acceptable range of pitch diameter for any given thread. The pitch diameter is shown as d2 in figure 1 above. There are several methods that are used to measure the pitch diameter. The most common method used in production is by way of a Go-NoGo gauge. A Go NoGo gauge refers to an inspection tool used to check a workpiece against its allowed tolerances. ...
See also The metric ISO screw threads are the world-wide most commonly used type of general-purpose screw thread. ...
British Standard Whitworth (BSW) is one of three imperial unit based screw thread standards which use the same bolt heads and nut hexagonal sizes, the other two being British Standard Fine (BSF) and Cycle Engineers Institute (CEI). ...
British Association or BA screw threads are a largely obsolete set of small screw threads, the largest being 0BA at 6mm diameter. ...
Threaded pipe and elbow National Pipe Thread is a U.S. standard for tapered (NPT) or straight (NPS) threads used to join pipes and fittings. ...
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