A compatible drill pipe connection targeting: maximum asset performance, ease of service, and customer satisfaction


Dynamic Geometry

The DLC drill pipe connection features the patent pending VARI-Flank thread form technology. This technology is intelligently designed to optimize the stress relationship between the connection cross section and the thread flanks.

Not only does the VARI-Flank thread technology provide enhancements that save time and money in the repair shop and on the rig, the DLC connection is compatible with Delta™ – the industry renown 4th Generation, high torque double-shouldered drill pipe connection.

Dynamic Break-in

Typically the best-practice procedure of 3 to 5 careful “Make and Break” cycles cannot be performed on newly machined connections at the shop, and it is is extremely time intensive to perform on the drilling rig. This results in as-machined threads being put into operation having tensile stress states with a greatly increased likelihood of connection damage or galling during makeup.

The VARI-Flank design allows for the makeup torque stresses to be optimally correlated such that an enhanced degree of break-in force is imparted on the thread flanks with a single “One and Done” break-in cycle. Desirable compressive stress is formed immediately into the thread flanks as the VARI-Flank design dynamically adjusts to the applied torque without requiring further break-out and make-up cycling.

Dynamic Torque

The VARI-Flank design works in tandem with the tool joint cross sectional design and geometry meaning DLC connection thread flanks not only break in quicker, they are continuously variable over time. As subtle changes occur in connection geometry when connections are subjected to extreme torque loads, the VARI-Flank design dynamically distributes compressive stress to lighter loaded thread flanks.

Whether being used with other DLC connections, or compatible connections, the dynamic VARI-Flank action continuously reinforces and protects the metallurgical microstructure of the steel itself from the harmful effects of abrasion, galling, and cold welding, further increasing extreme torque resistance and delaying need for repair.


DLC 425 and Delta™ 425 Compatibility Testing


Compatibility testing is performed where combinations of DLC and Delta™ box and pin connections are cycled repeatedly at standard and enhanced makeup torques, and then subsequently broken-out and studied for damage.

In all approved designs, no damage may be induced on either connection family during testing to ensure the performance and behavior characteristics of the DLC connection meet all expectations.

ConnectionTool Joint ODTool Joint IDStandard Makeup TorqueEnhanced Makeup TorqueTensile StrengthData Sheet
DLC 4255.250″3.000″26,000 ft-lbs30,300 ft-lbs786,400 lbsDownload
DLC 5446.625″4.000″50,300 ft-lbs58,700 ft-lbs1,211,500 lbsDownload


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DLC drill pipe is not affiliated, associated, authorized, endorsed by, or in any way officially connected with Grant Prideco Inc., or any of its subsidiaries or its affiliates. All product and company names are trademarks™ or registered® trademarks of their respective holders. Use of them does not imply any affiliation with or endorsement by them.


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