Types of Kelly Bars: Matching the Tool to the Task

Types of Kelly Bars: Matching the Tool to the Task

Kelly bars come in several configurations, each optimized for different soil conditions and drilling requirements: Vigorlink will explain the types and functions of the different Kelly bar

Interlocking Kelly Bars

These are specifically designed for drilling into hard materials where significant crowd force application is needed. They feature drive rails with locking pockets that interlock each telescopic element to the inner following one, allowing maximum torque and crowd force transfer. When extracting from the hole, a combination of lifting and rotating counterclockwise unlocks the sections.

Friction Kelly Bars

As the name suggests, these bars transfer torque through frictional contact between drive rails on the outside of each section. They don't require locking mechanisms, making them faster to lift and lower. Friction Kelly bars are typically used for deep piles in medium-hard soil conditions and are normally supplied with 4 or 5 telescopic elements.

Full Lock Kelly Bars

These are specialized versions that provide maximum locking capability, often used with specific drilling rig models like IMT, Mait, and XCMG rotary drilling rigs

Kelly bars may not be the most glamorous component of construction equipment, but they are undoubtedly one of the most critical. Without these telescopic workhorses, the deep foundations that support our modern infrastructure—from skyscrapers to bridges to high-speed rail systems—simply wouldn't be possible.