Mechanical lock type drilling kelly bar By sirthin sara @Pylon

[@SARUKING0122]

this is very helpuful to understanding the machanism of interlocking kelly bar. Thanks

[@sowen121]

bucket never gets emptied

[@dadarocks1]

clear explanation , very nice video.

[@kellybarfactoryamychen5354]

Excellent!

[@invisiblenavigateur315]

Good