Key Takeaways:
- Kelly bars transmit torque efficiently and adapt to different rotary drilling rig capacities, ensuring safe operation across diverse soils and rock formations.
- As a customized service, Everstar has manufactured up to 8 section for low head room Kelly bars, allowing contractors to match rigs to project where low head room construction is needed.
- Section counts six, seven and eight are for low-headroom Kelly bars, which determine achievable depth and efficiency in low head room operating scenario like under a bridge.
- Custom Kelly bar solutions ensure proper torque, wear resistance, and alignment with rig specifications, optimizing performance for all standard Kelly bars and specialized main products.
- Interlocking Kelly bars provide secure engagement between segments, supporting deeper projects, maintaining torque transfer, and enhancing stability for medium to large-diameter piles.
- Friction Kelly bars offer controlled torque and maneuverability, ideal for compact or shallow projects where flexibility and limited drilling depth are required.
A Kelly bar is made of connected segments that transfer torque and support the drill string during deep foundation drilling. Common setups use up to 6 sections, typically 22 meters each section, with adequate strength to handle large loads and protect outer surfaces.
Everstar provides custom kelly bars configurations up to 6 or 8 sections. Each telescopic segment adapts to varying soil and rock formations, and the right thickness combined with section count determines achievable depth, efficiency, and overall performance on any drilling rig.
This article explores how each Kelly bar section type is used. Understanding section count, diameter, and configuration helps ensure safety, operational efficiency, and consistent results for future projects without downtime or wasted effort.
Overview of Kelly Bar Sections
In a rotary drilling rig, a Kelly bar is made of connected segments, with each segment acting as a telescopic Kelly bar. The total section count determines achievable drilling deepness, efficiency, and suitability for specific soil and rock soil conditions.
What Do We Mean by “Sections”?
Each section is a telescopic segment that fits into the next, allowing the kelly bar to extend or retract as needed. Standard configurations of these drilling rigs range up to 6 sections, with each segment typically around 22 meters, following Everstar’s standard specifications and ensuring proper engagement with lock recesses.
Why Kelly Bar Section Count Matters
Section count directly impacts the depth of drilling. For instance, fewer sections may limit reach, while exceeding the rig’s force capacity can cause strain or wear. Customizing section count per project and rig ensures safe, efficient, and effective drilling operations.
When to Use Different Kelly Bar Configurations
Choosing the right Kelly bar configuration depends on project depth, drilling needs, and rig capacity. For example, a three-section bar may suit shallow projects, while a five-section Kelly bar allows greater reach. Section choice ensures efficiency, safety, and proper torque and crowd force management during rotary drilling.
Three-Section Kelly Bars
Suited for compact setups and shallow to medium-depth projects, each tubular Kelly section strikes a balance between manageable depth and easy handling. This configuration supports efficient drilling, reduces strain on the rig, and maintains consistent force transfer under typical drilling requirements.
Balancing Drilling Depth with Interlocking Kelly Bar
Three-section setups often employ an interlocking Kelly bar system for secure engagement between segments. This design ensures stable torque and crowd force while allowing moderate depth with minimal strain on the drilling rig.
Four-Section Kelly Bars
Commonly used for general construction foundation work, this configuration works with standard rigs and medium-depth projects. It provides reliable reach while maintaining mechanical locking mechanisms and force within safe limits, ensuring stable and efficient drilling operations.
Interlocking Kelly for Medium-Depth Projects
Four-section bars incorporate a lock Kelly bar system to enhance stability across multiple tubular segments. The mechanism supports medium-depth drilling depth, allowing safe torque transfer while maintaining proper alignment between the drill pipe and rotary drive components.
Five-Section Kelly Bars
Five-section bars are used when projects demand greater depth, such as rock foundation or specialized piling work. This configuration provides flexibility, allowing rigs to handle added length while maintaining consistent force transfer and efficient operation.
Robust Stability for Extended Reach
To achieve maximum extended depth, multi-section bars (such as those with five or six segments) utilize the Interlocking Kelly bar system, which provides robust stability.
Interlocking or multi-locking Kelly bars are designed for deep drilling applications in construction projects or rock foundations. This ensures secure force transmission, handles higher total weight, and allows efficient operation for large-diameter piles without compromising performance. The longest Kelly bar customized by Everstar is five sections, 26 meters, with an effective drilling depth of 122m.
Specialized Kelly Bars for Low Headroom Access
Highly segmented bars, such as those with six or more sections, are typically reserved for specialized for deep foundation projects carried out with limited head space for construction, such as under a bridge. In such cases, section length can typically be 2-3 meters, and traget drilling depth is reached with more sections.
The one with the most sections customized by Everstar is an 8-section Kelly bar with a low head room design.
Interlocking Kelly Bar for Maximum Drilling Depth
Six-section bars use either a friction Kelly bar or an interlocking Kelly system to maintain engagement over extended drilling length. This configuration supports high crowd pressure and force, optimizing stability and efficiency for piling rigs and large-scale construction projects (see U.S. Department of Transportation foundation engineering resources).
Customization Options from Everstar
Beyond customer satisfaction, Everstar offers matching drilling tools and standard Kelly bars tailored to project needs. When customizing a rotary drilling rig, considerations include total length, section count, bar type, and the square head drive connection that links the rotary drive to the drill pipe.
Matching Section Count to Rig Specs
Customizing section count to rig torque, crowd pressure, and the Kelly bar’s box size prevents mismatches. Correct alignment ensures safe operation, efficient force transmission, and consistent performance across deep piles and higher scale projects, protecting both outer bar and key components of any drilling rig.
Standard vs Special Configurations
The 6×22 m setup on kelly bars is one of the maximum single section length, offering reliable depth and wear resistance. Special configurations are possible based on project feasibility, including interlocking Kelly bars, friction Kelly bars, and bars optimized for dense sand or other challenging soil conditions.
How Everstar Machinery Supports Contractors
Everstar provides expert guidance on section count and bar type, ensuring correct lock Kelly bar or telescopic setups. This helps maintain optimal torque transfer, protects the terminal joint, and ensures safe, efficient operation during heavy rotary drilling projects.
After-sales support includes certified spare parts, drive keys, and components to maintain drive ribs and the outer bar in top condition. These measures extend service life, keeping piling rigs performing reliably under demanding drilling conditions.
FAQs – five-section kelly bar
How many sections can a Kelly bar have?
Everstar has manufactured up to 8 sections for low-headroom Kelly bars. The section count determines achievable depth, torque transmission, and suitability for varying soil or rock formations. Correct selection ensures safe and efficient operation on any rotary drilling rig.
What is the most common Kelly bar configuration?
The Kelly bar configuration will depend on the project requirements to provide reach and support high-torque operations as needed. This configuration is compatible with hydraulic rotary drilling rigs, balancing performance, stability, and drilling tools to effectively handle large-diameter and deep piles.
Can Everstar customize Kelly bars for specific drilling rigs?
Yes, Everstar customizes interlocking Kelly bars and telescopic setups to match rig specifications, crowd system concurrently, section length, and bar type. Custom solutions optimize torque, protect the steel pipe, and ensure safe, efficient drilling under specific project conditions.
Conclusion – Kelly Bar From One to Six Sections in Practice
Kelly bars range from one to six sections, each with specific advantages. For instance, a three-section Kelly bar works well in urban projects with limited space, providing manageable depth range and maintaining maximum torque without overloading the drilling rig.
Six-section configurations are the go-to choice for deep piles in bridges or high-rise foundations. These standard Kelly bar setups provide extended reach and stability, transferring torque effectively across the entire length while ensuring the rotary table and lock devices operate within safe limits.
Kelly bar length and section are determined by the drilling depth, thus, the project-specific customization is crucial. Choosing between an interlocking or a friction Kelly bar depends on soil and ground conditions. Everstar provides a complete guide to the different Kelly bars‘ main products designed for efficiency, durability, and extended service life.
Custom Kelly Bars, Built for Your Project
Contact Everstar Machinery for custom-engineered Kelly bars in 1 to 6 sections, tailored to your rig specifications and project requirements.
Production is supported by its Industrial Development Zone in China, providing high-quality drilling tools with expert support and reliable after-sales service.
