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Company Profile

Baoji Thread gages Co., Ltd was founded in September 2007 with a registered capital of 5 million and a gross investment of more than 30 million. It is a domestic technical enterprise focusing on the production of various thread gages, oil-specific pipe gauges and petroleum-specific pipe gages and a variety of special button thread gages.


The company is well-equipped with more than 30 sets of brand-new equipment, including general and CNC lathes, milling machines, internal and external cylindrical grinders, surface grinders, vertical shaft rotary table grinders, magnaflux, CNC marking machines, etc. The company imports the world's advanced Matrix internal and external CNC thread grinding machines and German Zeiss three-coordinate thread measuring machines to ensure the processing and measuring accuracy of products from manufacturing to product testing, and the annual production capacity of up to 2500 sets of thread gauges.


At present, the company has more than 50 employees, including 3 senior titles, 3 intermediate titles, more than 30 technical workers, and senior technicians with more than 30 years of experience in designing and manufacturing thread gauges. He has participated in the drafting and review of API SPEC 7-2, API SPEC 5B, GB/T 22512.2-2008 (Petroleum and natural gas industries. Rotary drilling equipment. Part 2: Threading and gauging of rotary shouldered thread connections), and API SPEC 5B 15th Edition 2008-10-01 (Threading, Gauging, and Inspection of Casing, Tubing, and Line Pipe Threads).


Baoji Thread gages Co., Ltd has been authorized by the American Petroleum Institute API (API SPEC 7-2-0680, API SPEC5B-0032) and is a professional company specializing in the production and sales of petroleum thread gage products in China. We have a perfect quality assurance system and a strict scientific management system.


Our products are used in CNOOC, Sinopec Shengli Oilfield, PetroChina Huabei Oilfield Company, Shandong Molong Petroleum Machinery Co.Ltd, China National Petroleum Baoji Petroleum Steel Pipe Co. Calibration, China National Petroleum Baoji Petroleum Steel Pipe Co., Ltd. and other major oilfields and oil-specific pipe manufacturers in China. The products also supply Weatherford oil Tools. Middle East LTD, Third Coast Gage & Calibration, Sonsan Sondaj Sanayii LIT.STI., Energogazpostavka., Co.Ltd., MTQ Oilfield Services WLL, Premium Co., Ltd, etc. are located in Asia, Africa, Latin America, Europe, America, Oceania, and other countries and regions.


Baoji Thread gages Co.,Ltd. will always adhere to the enterprise management strategy of "Take quality as a premise of competition, Take the market as the operation orientation, and strive to create international and domestic markets", constantly pursue the improvement of product quality, steadily improve brand awareness, and gradually make  "SRT" into a brand trademark of thread gauges in the petroleum equipment products industry.

Use professionalism to make you confident and let success praise you

Since its establishment, the company has been pursuing the service tenet of "customer first, quality first", and has won the trust and support of our customers with a good reputation and excellent quality. In the face of the rapidly changing technological innovations and increasingly fierce market competition, we will work together with new and old customers in the future to make new contributions to the process improvement and efficiency improvement of our customers, to produce thread gauges series that satisfy our customers, and to provide after-sales service that satisfies our customers.

Tenacious fighting spirit

Perseverance and never give up easily. Even in the face of adversity, we will be tenacious and hardworking and strive for performance without flagging, so that we can have a broad and compatible vision of the world to create the company's ambitious future.

indomitable Enterprising spirit

Insist on the Scientific Outlook on Development to guide the practice, constantly enterprising, never satisfied, and strive to build "integrity, passion, pragmatic, cooperation" enterprise, to achieve the leaping development of the company.

Full-hearted dedicationspirit

Efforts are made to promote the healthy and rapid development of the company's career with excellent job performance and industry civilized image while realizing the pursuit of personal value.

Petroleum pipe thread gage product introduction and use of maintenance

API thread gauges as a gauge with the versatility of gauges is a measurement method to obtain accurate results. Unlike the universal measuring tool, the oil pipe thread gauges with taper indirectly reflect the base level pitch diameter of the thread to the axial direction and realize the measurement process through the standoff value. The process of testing products with oil pipe thread gauges is also a comprehensive test of the rationality of the cumulative error of every single parameter of the product thread (pitch, taper, flank angle, and pitch diameter gauge point), which is a measurement process that cannot be replaced by simple pitch diameter test. Therefore, the correct use, maintenance, and repair of oil pipe thread gauges are particularly important.

The relevant value recognition of petroleum pipe thread gauges

To learn to use a set of qualified thread work gauges, we must first use standoff data provided by the gauges reasonably and correctly and check whether the gauges have calibration certificates or quality certificates, check the standoff values in the calibration certificates of the gauges to find out which data are related to the inspection products and whether these data meet the requirements of API SPEC 5B and API SPEC 7-2 specifications. Only these standoff values that meet the requirements of API SPEC specifications can be used. These data are used as follows:



API Spec 5B 油管、管线管、圆螺纹套管、偏梯型在校对规和工作规之间对应的紧密距S,S1,P及P1值



工作规检验产品的内,外螺纹之间的P1,A+(S1-S)值

公差P和P1A+(S1-S)
所有规格的管线管±1p
8牙/in 圆螺纹套管和油管±1p
10牙/in 圆螺纹油管±1 1/2p
偏梯形螺纹套管+1/2p+0
-0-1/2p



API Spec7-2螺纹量规检产品S2值

工作塞规测量产品内螺纹紧密距 : ( S-S1 ) 0~+0.25 mm

工作环规测量产品外螺纹紧密距 : S2 -0.13~+0.25 mm


Workplace use of gauges

The gauge must be cleaned with 120# gasoline and visually inspected for bruises, burrs, or other foreign matters on the threaded surface before use. It should be ensured that the thread surface is clean and free of foreign matter before the gauge is used.

When using a plug gauge or ring gauge in the process of thread turning, the gauge should be slowly rotated in by hand, and when the gauge is rotated close to the base surface, it should be returned a few turns to make sure that the rotation is in a normal state before tightening. Do not rotate and withdraw quickly to avoid the second surface bruising caused by the gap change.


Maintenance and storage of petroleum pipe thread gauges

Separate storage, dedicated management, and the establishment of a ledger system. Gauges need to be placed in sets of single pieces, available gauges shelves.

The gauges should be returned to the relevant storage department as soon as possible after use, and the functional department should clean and oil the gauges returned after use and store them as required. Avoid the gauges used in the field being left in the workshop for a long time.

Clean the gauge with 120# gasoline and coat it with enough anti-rust oil for storage, the storage place requires a temperature of 20°±1, and the room should ensure ventilation and dryness.

Newly purchased gauges need to be unpacked and re-cleaned and oiled for maintenance every six months.

The calibration technician should inspect the gauge in use from time to time to remove surface rust spots, and thread surface foreign matter (such as bruises burrs, scratches, etc.). Ensure that the gauge is in a good condition. The gauger shall establish and manage a standing book to record the product information, wear information, calibration information, and pick-up information of the gauges. The gauger shall regularly check the stored gauges to ensure the reliability of their use, and periodically submit them to the measurement department for calibration according to API standards.

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