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Anyone know about API (oilfield) threads?

metaltech

Hot Rolled
Joined
Feb 7, 2007
Location
midcoast U.S.A.
I've been asked to assist with the set-up of a job on a CNC lathe to cut female threads in a piece of steel tubing. I was given a hand-drawn "print" with basic dimensions, but not enough on the thread. The thread is tapered, has round crests and roots, 10 threads/inch. The notation that points to the thread says "1.315 x 10NU". The part itself is called a collar, and connects long pieces of pipe that go down into the ground. (At least these people call it a collar. I've also come across the terms pin and box, but I don't know if these are just oilfield terms for the male pipe and female coupling.)

I need to know several things:

1) taper angle
2) how to check the thread - does someone make guages?
3) what tooling company makes a good threading bar and inserts? I assume a topping-type insert is needed.

I looked on the API website and found that they offer a few billion publications for the oil industry! I found a listing for threading tubing products, but it's well over $100 for 48 pages, and I don't even know if it's what I need. I only want the specs for one thread. Does anyone know of other sources for this info?

I've put all the time I can afford into searching the PM website and not come up with my answer (maybe I don't know how to search properly). So, I'm appealing to all you smart types out there. Thanks for your help!!

metaltech
 
I Can't be much help, but I used to cut round bottom 8 threads on oil pipe in Louisiana many moons ago. Don't remember the taper, but these had a special form tool that cut the round form in the root and on the crest. They were fussy about the finish coz it had to hold a lot of pressure.
At any rate, there does (did) exist a good HSS form tool for them.
 
API Tubing

That thread is 1" 10 round non-upset tubing. You can probably find specs on it from someone that makes API tool joint gages. We used to do business with Lone Star Gage in Houston. They have a website.

I'm sure some of the oilfield folks will have more information. That size was not very common where I worked but we had a few joints on hand.

Good luck,

Terry
 
I ask the question a while back, how can drill pipe stay together in strings thousands of feet long and it turned into a very good discussion on drill pipe, threads and oil field usuage. I don't know how to link the thread but if someone can post a link to it it might be helpful.
 
http://www.practicalmachinist.com/vb/showthread.php?t=74702

Here is the link to the oil patch thread discussion. I, like many others here, have cut many NU and EU tubing threads. We had TIN coated carbide inserts that MIGHT have been special made. Try Bass tool in Houston if you want to find inserts, I believe they were the suppliers. You can probably find the gages, we were always given the gage by our customer, (Baker Hughes) but you can probably rent them as someone else already said.
 
Wow, I hit the jackpot! You guys are great. Thanks for all the helpful posts. Well, boslab's didn't help, but it did make me chuckle, which I always need.

Terry, thanks for the tip on Lone Star Gage. Looks like they have what I'll need.

David, good tip on Bass Tool. Jeez, they rep a lot of stuff. Took several minutes for me to scroll through all the products they handle. I came across Tool Flo, which makes the inserts. Looks like they are the cutting tool kings for oilfield threads. Also, I had run across the thread discussion you mentioned (I noted that you didn't call it the thread thread, heh, heh). It was quite informative, just lacking on the specifics that I needed.

Again, thanks all for the replies. This is by far the best website I've seen for machining. Plenty of smart people here.

metaltech
 
No problem, Metaltech. Always glad to help. I actually found an old drawing for a 3.500 O.D. E.U. pin thread, 8 t.p.i., 3/4 t.p.f. It has been sitting in my tool box since 1991. This drawing calls out the ring gage to be flush with the end of the pin, plus or minus .125 which is very lenient tolerancing IMO. These are not too bad to cut at all, the inserts top the crest of the thread. Be sure to use plenty of oil. I always used Tapmatic.
 
I still have the fat little Drilco (Smith International) book if any info is needed on the bigger API threads, of which there are an amazing number :)
 
You can purchase those inserts from Tool Flo, Vargus or Seco also has that form. The company I work for specializes in small tubing for the oilfield.
 
February issue of Tooling & Production , had alot of info on oil pipe threads .
These are some of the most demanding , and paper trail intensive , machined parts .
Every thread in an oil pipe string is traceable to whoever worked or reworked it .
Considering that some of these strings are over 16,000 feet long , there are millions of $ at stake if a single one fails .
I am quite intimidated , and have great respect for someone who does this kind of work .
 
MetalTech,
If you need more information on this tubing thread let me know, As John Oder said I have information on this thread to cut. Tool Flow is the only company out there that handles carbide inserts to cut this thread that I'm aware. May try Cutting Tools, Inc, out of Houston, they handle Tool Flow inserts and tooling. I don't deal with Bass Tool.
 
Sorry to not respond for several days. Been overly busy with my son's high school robotics competition. That's over now, so I'm finally getting a chance to catch up on the rest of the world.

Again, thanks for all the tips and offers of help. I'll see what answers I get to e-mails sent to Tool Flo and Lone Star. If I get (more) confused, I'll look you guys up again.

Regards,

mt
 
I Need Some Help With Api Thread Specs

Hello Guys
Onyone Have A Api Thread Specs Drawing? Please Tell Me Where Do I Go To Buy Full Binder With All Type Api Thread ? Thanks Very Much Guys.
 
Buy Thread Drawings

Our company has put together some of the most commonly used API thread drawings.
It took us several hours and money to have them done and are offering them for sale.
The cost is $10.00 per set and includes the both the pin and box drawings.
Here is the link if interested: http://www.baumanmachine.com/THDDRAWING.html
Regards,
Okiemachinist
 
It sounds like you want API 10 rd Kennametal, Carmex, Tol flo all will have this thread form in a 3/8 insert. If its casing your talking about it's 3/4 inch per foot like pipe. I have information in a note book some place with the specs, but I would have to have alot more information from you, like the diameter. I've done then up 7 3/4 inch. drop a line if you haven't found it yet and I'll look it up tomorrow.
 
I have drawings to most of all of the "public domain", incl. API thds, threads used out in the "oilfield" today redially available. I don't and won't publish a book of them. But if there is a particular thread you want to cut I can provide the necessary machining dimensions to cut it for a given thread.
Let me know your needs.

Ken S.
 
I worked in industry for 35 years. I have found if demensions are not on the print it is best to contact the person that sent you the print. If they supply you with the wrong information then you will get paid for your work if it is wrong. If you guess and it is wrong then you don't get paid.

I know a little about oil well drill bits but not enough to give you any helpful information. I know there are many many different size drill bits some for oil some for gas some for water all with a different thread size.

30 years ago I found a brand new oil well drill bit at a lost luggage store I bought it for $4 they had no idea what is was. I resold it to an oil well supply company for $2500. The said it was worth $5000.

One of my first jobs after college was working for a company buying up mineral rights in Tennessee. I contacted land owners and offered them big $$$ for the oil rights. It was free money to them at the time it was known the whole state of TN, KY and several other states have deep oil several miles deep. The technology was not available at that time to drill wells that deep but now it is. The US Government does not want any of the oil drilled and pumped out because if we ever get into another world war that will be our last resort oil supply.
 








 
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