ISO 7-2: Pipe Threads where Pressure-Tight Joints are made on the Threads; Part 2: Verification by means of Limit Gauges
ISO 7-2:2000 Foreword
This second Edition cancels and replaces the first edition (ISO 7-2:1982).
ISO 7-2:2000 Introduction
This revision of ISO 7-2 has been undertaken with the aim of providing a unified gauging system (1)(2) which could be adopted worldwide and thus eliminate the differing results (3) obtained with the use of gauges in accordance with ISO 7-2:1982 and existing national practices. This revision also includes details of plain ring gauges to provide additional means of checking ISO 7-1 external threads and a parallel modified thread form check ring gauge for checking taper full form treaded plug gauges.
ISO 7-2 Scope
This part of ISO 7 specifies a process using limit gauges, for the validation of taper internal and external threads and parallel internal threads on piping systems components and other products, the dimensions and tolerances of which are detailed in ISO 7-1. The gauging system described may not be suitable, without special precaution, for gauging of threads on injections moulded plastic workpieces. This part of ISO 7 does not cover completely all the requirements necessary for full control of thread quality and dimensions. Additional control of tools and equipment and visual inspection during production are required to ensure complete compliance with ISO 7-1, for example the length of useful thread on internally threaded workpieces should be checked by direct measurement. Annex A gives a summary of the gauges included in this part of ISO 7, together with details of the thread elements controlled by each gauge and gauge identification numbers. In the event of a dispute over compliance with the requirements of ISO 7-1, the gauges in this part of ISO 7 are to be considered as decisive for the thread elements which they control on the workpieces.
1. Unified gauging system: The ISO 7-2:2000 gage design was protested by Japan; UK and USA representivies on the ISO committee; regardless; the standard was ratified.
2. Gage 3 has a single point contact on the taper thread which could rapidly wear and create erroneous readings.
3. Eliminate the differing results: A laudable goal, but with tapered pipe threads an impractical goal.
4. ISO 7-1 is technically equivalent to EN 10226-1 and EN 10226-2 combined.
5. ISO 7-2 is technically equivalent to EN 10226-3.
Original Posting: 11/6/2012
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