ASME B [Revision of ASME B (R)] Unified Inch Screw Threads (UN and UNR Thread Form) A N A M E R I C A N N AT I O N A L STA N DA. Nominal Diameter, Major Diameter Inch, Major Diameter mm, Tapping Drill Size mm, TPI, Pitch mm. 5/16″ – 20 UNR, , , , 20, 5/16″ – IFI NOTES: 1. ASME B is a standard developed through the procedures of The This abstract presents the requirements of ASME B as they ap- ply to the.
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The intention is to provide accurate information; regardless; errors may exist in the supplied information. There are several other changes in the standard, as would be expected.
Well here we are in and I daily get screw thread gage requests for the N-series thread. How do we get the message across that when a standard changes, go with the flow and change your drawings and internal procedures to accommodate the revised version of reality?
Revision to some values in Table 2: The N-series is fully mechanically interchangeable with the UN-series. The first sentence in the Foreward is their strongest move to eliminate the N-series screw threads once and for all.
This statement could be used as authorization to deviate from a drawing. To purchase a copy asm an Authorized Reseller.
UNR Thread ASME B1.1-2003
I hope we are not we looking at another 60 years of controversy. This standard is also available to be included in Standards Subscriptions.
The seemingly random number changes hit many of the listed standard screw thread sizes. If the pitch diameter stated on the drawing is 0. It does not eliminate the UNS designation, bb1.1-2003 will eventually restrict their use to those willing to do the math to engineer the thread because as of the next revision of the standard the chart will disappear.
Second, the thread nomenclature was changed from N to UN. The standard has been revised six times, and still people insist on using the version of the standard! Because of this, most gage makers are not moving to change to the new pitch diameters. After all that explaining the requestor replies that: You may delete a document from your Alert Profile at any time.
Several variations in b11.-2003 form have been developed for unified threads; however, this Standard covers only [Unified] UN and UNR [external threads only] thread forms. This standard is not included in any packages.
The difference is only 0. This statement is strong because it has been printed in the now current standard.
ANSI/ASME B Change Summary
To get the complete details, buy a copy and read the Foreward. I expect that paragraph 8. This is a seemingly innocuous statement, but this is where the pitch diameters change by 0. Top Gage Crib Worldwide, Inc. If the drawing change process is too daunting, issue a blanket engineering change order dictating that 60 degree inch series screw threads will be made to the most current same of B1.
The pitch diameters are the most visible of the numbers that changed. So what changed in the B1. First the pitch diameters of the threads were adjusted by 0. Proceed to Checkout Continue Shopping. The drawings are not under his control and it takes an act of congress to get a drawing change. Standards Subsctiption may be the perfect solution.
B11.1-2003 Alert Profile lists the documents that will be monitored. As the voice of the U. We have no amendments or corrections for this standard. This is something that all engineers need to address. The N-series thread is obsolete. Make drawing changes at the detail level of product designs.
Begin an education process aimed at third-party government inspectors to train them to understand and work to the now current version of B1. If the document is revised or amended, you will be notified by email. Subscription pricing is determined by: Nonmandatory Appendices A through E contain useful information that is b1.11-2003 to the sections of this Standard. If accuracy is critical, base your final decisions on the data provided in the root document: Two basic things in B1.
When the drawing indicates the N-series screw thread, it is known that the thread is specified in Asms. The N-series screw thread was replaced in with the UN-series.
UNR Thread ASME B
Need more than one copy? The print requires the N-series and he does not dare deviate from the drawing.
For easy reference, a metric translation of this Standard has been incorporated as Nonmandatory Appendix C. This Standard specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads. The authors of the standard are doing their part to eliminate the N-series screw threads.