Kelly bars na important tins for deep foundation construction, wey dem specifically design for use with rotary drilling rigs to make drilling tools enter ground well well. Dis special drilling tools get strong body, wey dem usually make from high-strength steel, wey make dem durable and reliable for difficult subsurface conditions. Dem work with simple but effective principle, Kelly bars dey connect to drill string and rotate with drilling rig, dey transmit torque and also allow for vertical movement. Dis special mechanism make dem fit drill deep boreholes and put foundation elements like piles and caissons for ground.