API published Addendum 3 to the Second Edition of API Specification 7-2 in September 2025, with an API Monogram Program effective date of April 1, 2026. 

The specification addresses threading and gauging of rotary shouldered connections.

The addendum revises provisions concerning stress-relief grooves and updates details in Figure 6. Its discussion highlights an engineering trade-off: the potential fatigue-life benefit of a stress-relief groove must be considered alongside its effect on connection strength. 

The official addendum should be consulted for the exact dimensional requirements and applicable conditions

For manufacturers and inspection teams, a practical review should connect the updated requirements with controlled drawings, inspection instructions and relevant personnel training. 

Where affected dimensions are involved, teams should check that their inspection equipment and methods are suitable for the required checks. 

Publication of an addendum should not, by itself, be treated as evidence that every existing thread gauge requires replacement.

When planning gauge purchases or calibration, clearly identifying the connection type, size and applicable specification helps suppliers understand the inspection task. 

Contact Shanghai Jingoo Petroleum Apparatus Co., Ltd. to discuss your thread gauging and calibration requirements.