Sharp Thread Tubing

As you are sparse with the details, I can suggest that you bring your own tubing to the 'party' at your local machine shop. Also bring the TPI and class of thread, depth and angle of thread, root diameter, radius at the crest and trough and they will easily figure out how to give you what you want. If there is volume production, just bring a sketch and the tolerances you want and they will price it for you. There is no better time to support your local machine shop and get a bargain also. Good Luck

Thk,but i need the detail to machine for my customer

Hello, Tell us more detail and you can expect a detailed answer. What are you trying to do with the tube and sharp thread, ie the end use? The Machinist Handbook has all the detail necessary to manufacture threads on a tube and or arm you with the details to buy the finished threaded tubing.

The minimum you need to divulge is the tube wall section and the TPI, (Threads per inch). Is there a mating part available to measure? Use a thread gage and then match that to the tables in the Machinists handbook. If you know what you want there is a good possibility that it is commercially available. 'Sharp thread' is not enough to go on.

Thk, I think is what they call 31/2 VR thread (API)

Friend,I got the thread detail,thk

It looks like an API thread.

You need the standards API 5D or API 5CT.

And also since these are API threads, the gauges are necessary.

I don't know where you are but the gauges for API are manufactured and claibrated only by a very few labs (and all are in USA, at least that's where we have to send our gauges for recalibration)

Thk, I had the gauge but i need the thread detail to machine (3 1/2 VR API Thread).

Friend,I got the thread detail,thk

Thk, it help alot to me

bentarrow,Is there any way tou can help to measure the tape 3" sharp thread tubing-Non upset with ball mic,Anyway i am confuse the drawing call for 3.5 sharp thd tubing but the ring gauge I.D is bigger than the part O.D dia 3.500" can you tell me why.

alfredngal,

I should have realized that your customer was referencing the basic thread callout by nominal OD instead of the nominal ID. API 5A refers to these tubing threads by nominal ID, so I naturally thought you were too. Today API 5B calls tubing threads by nominal "pipe body OD" - and for Line Pipe threads they designate them by nominal ID. So it gets confusing very quickly if you are new to the business of machining oil well tubular threads.

So it appears you are trying to cut what 5A calls "3" Sharp-Thread Tubing-Non Upset". So the critical dimensions are as follows:

Nominal Pipe OD" 3.5"

11-1/2 Threads per inch

Taper: .0625" per inch

Pitch Dia. of Plug Gage at Gage Pt: 3.43043"

Major Dia. of Plug Gage at Gage Pt.: 3.48835"

Distance from end of plug gage to gage pt.: 1.8777"

Distance from small end of pipe to gage pt: 1.8777"

Distance from Gage Pt to Vanish Pt.: 0.4348"

Height of Pipe Thread (Truncated): .0661"

As far as measuring the taper, ball mikes can get you "in the ballpark", but we prefer to use a Mitutoyo 3"-4" Thread Micrometer (Model # 126-140) with a set of #4 anvils (M4-C & M4-V). Mark the crest of the thread at .250" away from small end, then mark the 2 crests 180 degrees opposite. Then mark the crest of the thread that is 12 threads away from 1st mark & also mark the crests of the 2 threads opposite from this last mark. Place the M4-V anvil over the 1st mark & M4-C anvil between the 2 crests marked 180 degrees opposite and take your measurement. Then repeat this procedure at the second location 12 threads away. If your taper is "perfect" you will get a difference in the two PD measurements (that are 12 threads apart) of .0652". This is a value that is compensated due to it being 1/2 thread beyond the 1" distance that the .0625" specification applies to.

I hope the above proves to be more helpful.

bentarrow thk again for help real appreciate for that detail,that what CR4 realy help to bring us together.

bentarrow; I have been searching for the same type thread, only for 2" and 2-1/2". Does API 5A have a complete table of dimensions similar to the dimension tables in API 5B; which shows dimensions L1, L2, L4, E1, etc?

Thanks, wjfergus

wjfergus,

Sorry for the delay getting back to you. I was sick for a few days up until a couple of days before Christmas. Been playing catch-up ever since.

Yes API 5A does have complete tables very similar to API 5B. In fact they have a few extra columns of thread dimensions such as diameters of root & crest at both small and large ends of the pipe.