API 7 Kelly
1, Standard: API 7-1; SY/ T 6509; or Non-Standards. 2, Type: Square Kelly; Hexagonal Kelly Steel Grade: AISI 4145 H 4, Size: OD (3 1/ 2”—6”); ID (1 3/ 4”—3 1/ 2”); Length (40”) 5, Cold rolling of thread roots 6, Stress relief groove 7, Thread surface ...