How to make an API thread on a steel pipe?

[mrturran]

I intend to put an API-thread on a massive steel core. The application is piling. Does anyone know which type of machine is used? (oil country lathe?) It´s the same thread that is used on oil pipes (one internal and one external). The steel bar is 8 meter long and have dimensions from 80 mm up to 180 mm. Since the bar is not straight it will cause serious vaibrations. Appreciate your assistance.

 

[KernOily]

There are standards for API threads, just like any other thread. You can get them from API.

One way would be to make a threaded stub. Cut off the end of the pile that needs the thread, cut the thread on it in a lathe, and then re-weld the end back on the pile. Grind the weld flush if needs be.

Oil country tubulars are done this way all the time. They just use a regular lathe, set up for the swing and the length. Discuss your need with a qualified oilfield machine shop. He will have the API thread standards. I can supply you with names if you need it.

Not sure why you want an API thread but I suppose you have good reasons. There are other perfectly useable threads out there also that might keep you from having to find an oil patch machine shop.





Thanks!
Pete

 

[mrturran]

Hi Pete,

Thanks very much.

The API-thread is of some reason standard for this piling application. Yes, please provide me with names if you have.

We need to thread it on a exsisting pipe and can´t weld a pieace on becouse of the application. Do you know about this process, to make a thread on a pipe? The bar will weight up to 1 mt. Thanks!