High-Precision API 7-1 Drill Stem Subs from China Suppliers – Reliable Factory for Durable Drilling Solutions
Product Application
Drill stem subs serve as critical components in drilling operations, acting as connectors between drill pipes and drill collars. Each sub features a drill pipe connection on one end and a drill collar connection on the other, enabling seamless integration of drilling equipment.
Crossover subs, a specialized type of sub, are designed to adapt to different connector types or sizes and connections.
The sub that connects the drill bit to the last drill collar is the bit sub.
Types of Sub
There is a wide range of subs available to meet the specific needs of modern drilling operations:
- Straight Crossover Sub (Box/Pin, Box/Box, Pin/Pin)
- Crossover Sub with Float Bore (Box/Pin, Box/Box, Pin/Box)
- Bit Sub (Box/Box)
- Top Drive Saver Sub (Pin/Pin)
- Kelly Saver Sub without rubber protector (Box/Pin)
- Kelly Saver Sub with a stretched on rubber protector (Box/Pin)
- Lift Sub (18 deg taper or squa
- Lift Plug (None/Pin)
Product Features
Premium Materials
We utilize only the highest quality, fully traceable 4145-H heat-treated alloy steel bars, ensuring superior mechanical properties in strict accordance with API and NS-1 standards. For applications demanding enhanced wear resistance and torsional strength.
Precision Threading
Threads are cold rolled to ensure a perfect fit and maximum strength. Standard phosphating of threads and seals provides exceptional anti-corrosion and anti-galling protection, minimizing the risk of galling during initial makeup.
Customized Solutions
We offer customized drawings and detailed product data tables upon request, enabling our clients to make informed decisions and select the perfect subs for their specific needs.
Frequently Asked Questions
What is the main function of a drill stem sub?
Drill stem subs serve as critical connectors between drill pipes and drill collars, enabling seamless integration of equipment during drilling operations.
What is a crossover sub?
A crossover sub is a specialized type of sub designed to adapt to different connector types, sizes, and connections in a drill string.
Which sub is used to connect the drill bit?
The sub that specifically connects the drill bit to the last drill collar is known as the bit sub.
What materials are used to manufacture these subs?
They are manufactured using the highest quality, fully traceable 4145-H heat-treated alloy steel bars to ensure superior mechanical properties and wear resistance.
How are the threads protected against corrosion and galling?
The threads and seals undergo standard phosphating, which provides exceptional anti-corrosion and anti-galling protection, minimizing the risk of galling during initial makeup.



