FES Kelly bars may be made in friction type and locking type, in 3, 4, 5 or 6 elements for some special occasion. For sake of common application, the external diameter is designed to be in universal dimension, such as 273mm, 299mm, 340mm, 377mm, 406mm, 419mm, 440mm, 470mm, 508mm, etc. High strength steel tube material is picked and heat-treated to arrange production, which enables the Kelly bars to work well under maximum torque of the torque output. Kelly keys and guides inside Kelly joints are made in highly wear-resistant material for a prolonged maintenance time. Special tooling is set up to ensure the straightness of tubes during welding process.
