Kelly bars


Kelly bars are key components in the execution of boreholes with hydraulic rotary drilling rigs. They transfer the torque of the rotary drive and the crowd pressure of the crowd system concurrently to the drilling tool. A Kelly bar consists of 2 – 5 telescopic tubular sections with a system of drive keys and lock recesses welded onto their outer surfaces. Standard Kelly bars are fabricated with a total of 6 drive keys on each section. The tubular Kelly sections are manufactured from high-tensile steel to ensure minimum weight at adequate strength.

  • 2 to 5 telescopic sections for depths of 15  – 100 m

  • Torque transfer from 120 – 480 kNm

  • Fully lockable Kelly bar (standard for all BG machines)

  • Friction Kelly bar for drill attachments

  • 6 drive keys with large lock recesses

  • Shock absorbing system by spring assembly

  • Standardized square Kelly drive stub for all drilling tools

  • Noise damping system (optional)

More information can
be found in our brochure:

Kelly bars

BK 200
BK 250
BK 260
BK 280
BK 300
BK 420
BK 500
BK 12
BK 15
Dia outer kelly(mm) 368 394 394 419 419 470 559 305 343
Number of elements 3/4 4 3 4 3 3/4 3/4 3/4 3/4
Drive adapter system I I I I I I I III II