Top hammer rock drill rods, also known as top hammer drilling rods, typically feature threaded connections to facilitate the transfer of impact energy from the drill rig to the drill bit. The thread types used for top hammer rock drill rods vary depending on the manufacturer, region, and drilling application.
R Thread (Rope)
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Low pitch, 12.7 mm rope threads with a small angle of profile.
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Sizes: 22 mm – 38 mm
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Good wear characteristics.
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Perfect for short hole Rock Drill Rod, such as subterranean digging, or single pass drilling.
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Applications that require infrequent uncoupling.
HM (T) Thread
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HM thread, sometimes known as "T" thread, has a higher pitch and a steeper profile angle than rope thread.
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Dimensions 35, 38, 45, and 51 mm.
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Superior wear characteristics, and superior coupling qualities.
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Ideal for numerous steel extension Rock Drill Rod.
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More torque capability.
EL Thread
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The HM thread's profile has a similar angle.
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Made to fit Rock Drill Rod with diameters of 60 mm and 70 mm.
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Steel to be used with the newest, most powerful rock drills.
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Excellent wear resistance and a readily decoupling pitch angle.
BE (ST) Thread (Tube Rod)
• A shoulder drive system is a thread (available in the bottom drive as well). To transmit the energy, the shoulders of the pin and box butt together.
• Superior wear characteristics and positive coupling characteristics
• Applied for drilling extension tubes using a variety of tube steels.
• Compatible with both surface- and underground-use high-torque-top hammer rock drills.
Choosing the right thread type for rock drill rods offers several benefits, including:
Compatibility: Selecting the appropriate thread type ensures compatibility between the drill rod and other drilling components, such as drill bits, couplings, and drilling equipment. A proper thread match prevents compatibility issues, reduces downtime, and enhances overall drilling efficiency.
Secure Connection: The right thread type provides a secure and robust connection between the drill rod and other components. This connection is essential to transfer the impact energy effectively from the drill rig to the drill bit, allowing for efficient rock drilling.
Durability: When the correct thread type is chosen, the connection between the drill rod and other components is strong and reliable. This enhances the overall durability and longevity of the drilling system, reducing the risk of thread damage or failure during drilling operations.
Optimal Performance: Different thread types may have specific design features that contribute to optimal performance in certain drilling conditions. For example, tapered threads can provide better energy transfer and stability in challenging rock formations. By selecting the right thread type, you can optimize drilling performance, productivity, and hole quality.
Standardization: Thread standardization, such as API threads, ensures interchangeability of drill rods and other drilling components from different manufacturers. This simplifies equipment sourcing, replacement, and maintenance, as standardized threads are widely
