WINTER 2014

NATIONAL INDUSTRIAL

NATIONAL INDUSTRIAL FASTENER & MILL SUPPLY EXPO SANDS CONVENTION CENTER, LAS VEGAS - OCTOBER 24-25, 2013 more photos on page 184

THE DISTRIBUTOR’S LINK 161 CUT THREADS AND ROLLED THREADS MUST MEET THE SAME REQUIREMENTS continued from page 42 Thread gage types and gage tolerances vary slightly between ASME B1.16M and ISO 1502, with the primary difference being in the external thread GO and NOT GO gages. The ASME external thread gages are adjustable and in ISO the gages are solid (non-adjustable). The size requirement differences between the two types are within a few 0.001 millimeters (0.0004 inches) of one another. Thread Acceptance Requirements: The thread acceptance requirements for industrial (nonaerospace) inch and metric threads are identical. Those are System 21 requirements as stated in ASME B1.3. The acceptations to this are socket products made to ASME B18.3 where ASME B1.3, System 22 evaluation is required. ASME B1.3, System 21 requires the following thread characteristics be evaluated: Thread acceptance requirements are the same regardless of the method in which the threads are produced. Both ASME B1.3 and ISO 1502 state that when a given product thread is evaluated using two different properly calibrated gages, where one accepts the thread and the other does not, the thread shall be accepted. It is suggested that this rule be followed whether the two gages are the same style or type, different style or type, or one is an ASME B1.16M gage and the other is an ISO 1502 gage. When these types of discrepancies occur, the detected differences have no discernable impact on the quality or strength of the threaded product being inspected. Conclusion Regardless of the method of thread manufacturing, the dimensional requirements for internal and external threads are identical. The same thread acceptance rules apply, and the physical and performance requirements of the nuts, bolts, or screws those threads are in or on are identical as well.