correlation between load rating and thread size on rotary swivel
correlation between load rating and thread size on rotary swivel
(OP)
I've been trying to figure out what the correlation is between the rotary swivel stem connection size and the swivel's load rating. For example, why does a 500 ton swivel have 7-5/8 LH API Reg connection and the 750 ton swivel the 8-5/8? Can't the 750 ton have 7-5/8 connection? I've checked API 8C and 7, but I don't see any section that requires a certain load rating to have a specific connection size. Is there an API specification that determines the relationship, or is it an arbitrary decision of the manufacturer? I would appreciate any help on this matter.




