NC Connections - Rotary Shoulder Connection - Thread Plug and Ring Gages - API Spec 7-2
NC Connections are Rotary Shoulder Connections having the V-040, V050 or V-055 Thread Forms. Gauging practice and thread inspection should conform to the requirements of API Spec 7-2. Thread Check, Inc. offers the complete range of API NC Thread Plug and Ring Gages to API Spec 7-2. Our engineering staff have served on various API gaging subcommittees and have worked in the energy industry for many decades. Thread Check's expert engineers can assist you with engineering and building custom gages. Thread Check is a proud member of the American Petroleum Institute.
Per API Spec 7 - Obsolescence Rotary Shouldered Connections
In 1964, at the API Committee on Drilling and Service Equipment, a new series of rotary shouldered connections was adopted in order to improve the service performance of drill collars and tool joints. 11 of the 13 NC sizes were approved as standard.
For the new style of connections, the size designation is a two digit number indicating the pitch diameter of the pin member at the gage point and the style is referred to as the number style or numbered connection – NC. These NC connections utilize a V thread form having a .065 inch flat crest and a .038 inch rounded root. This form is specified as the V-0.038R form. This V .038R form mates with the V-0.065 form that is employed on all API internal flush ( IF ) connections and on the API 4 inch full hole ( FH) connection.
All API IF and FH connections are now considered obsolescent and appear in the appendixes I,J, and K of API specification 7.
Of the new NC connections there are 5 sizes that have the same pitch diameter, taper, pitch, and length of thread as the corresponding size in the IF style and one corresponds to the 4 FH connection.
These 6 connections in the number style can be gauged with the same gauging practice and same gauges required for the equivalent connections.
|NC10-P||NC10 Thread Plug Gage||Add|
|NC10-R||NC10 Thread Ring Gage||Add|
|NC12-P||NC12 Thread Plug Gage||Add|
|NC12-R||NC12 Thread Ring Gage||Add|
|NC13-P||NC13 Thread Plug Gage||Add|
|NC13-R||NC13 Thread Ring Gage||Add|
|NC16-P||NC16 Thread Plug Gage||Add|
|NC16-R||NC16 Thread Ring Gage||Add|
|NC26-P||NC26 Thread Plug Gage ( 2 3/8" IF interchangeable )||Add|
|NC26-R||NC26 Thread Ring Gage ( 2 3/8" IF interchangeable )||Add|
|NC31-P||NC31 Thread Plug Gage ( 2 7/8" IF interchangeable )||Add|
|NC31-R||NC31 Thread Ring Gage ( 2 7/8" IF interchangeable )||Add|
|NC35-P||NC35 IF Plug Gage||Add|
|NC35-R||NC35 IF Ring Gage||Add|
|NC38-P||NC38 Thread Plug Gage ( 3 1/2" IF interchangeable )||Add|
|NC38-R||NC38 Thread Ring Gage ( 3 1/2" IF interchangeable )||Add|
|NC40-P||NC40 IF Plug Gage||Add|
|NC40-R||NC40 IF Ring Gage||Add|
|NC44-P||NC44 IF Plug Gage||Add|
|NC44-R||NC44 IF Ring Gage||Add|
|NC46-P||NC46 Thread Plug Gage ( 4" IF interchangeable )||Add|
|NC46-R||NC46 Thread Ring Gage ( 4" IF interchangeable )||Add|
|NC50-P||NC50 Thread Plug Gage ( 4 1/2" IF interchangeable )||Add|
|NC50-R||NC50 Thread Ring Gage ( 4 1/2" IF interchangeable )||Add|
|NC56-P||NC56 Thread Plug Gage ( 5" IF interchangeable )||Add|
|NC56-R||NC56 Thread Ring Gage ( 5" IF interchangeable )||Add|
|NC61-P||NC61 Thread Plug Gage ( 5 1/2" IF interchangeable )||Add|
|NC61-R||NC61 Thread Ring Gage ( 5 1/2" IF interchangeable )||Add|
|NC70-P||NC70 Thread Plug Gage ( 6 5/8" IF interchangeable )||Add|
|NC70-R||NC70 Thread Ring Gage ( 6 5/8" IF interchangeable )||Add|
|NC77-P||NC77 IF Plug Gage||Add|
|NC77-R||NC77 IF Ring Gage||Add|