4145H square or hexagonal Rotary kelly square kelly

Kelly is the main driver of the whole drill string.It transmits torsional energy from the rotary table through the drill string to the bit at the bottom of the hole. Kelly is a long square or hexagonal.precision machined heavy steel bar that is supported by the swivel through the rotary table and is connected to the first joint of drill pipe in the drill string.

Straightness of the kelly is very crucial in the manufacturing process, thus straightness inspection are carried out before, during and after each machining operation. The flats are precision-milled to API specification.All milling processes are performed on specially designed rigid kelly mills to ensure tight tolerances and high quality drive section.Each kelly is furnished with a pressed steel thread protectors.