Drill Pipe Threads 1

[burgy]

I am looking for specifications for 2" 4 TPI 10 degree tapered drill rod joints very similar to API but cannot find dimensions for 2" Have reference to a NC thread in tool suppliers catalougue but angle is wrong as well as diameter. Length of thread is 2" I have measured off a sample for the male tread(pin) and machined a sample which appears ok but female is a problem because of the size of the tool tip for 4TPI
best regards to all
Burgy

 

[Cockroach]

You might have a rotary shoulder connection. Sourcing Table 9.1 for API Spec 7, the closest thing I can find is NC23 which has the following product dimensions:
1) Small diameter of pin: 2 1/16,
2) Gauge of thread: 4 TPI,
3) Pin length: 3 inches,
4) Large diameter of pin: 2 9/16,
5) Thread form: V-0.038R.
Doing the math, the half angle of the pin is 4.76 degrees, I would get 10 degrees full angle, correctly corresponding to the listed 2 in/ft.

I realize you have mentioned attempting to source the NC catalogue to no avail. You may be right, nothing listed with pin length of two inches even. Perhaps you're dealing with a bastardized thread?

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[burgy]

Spoke to customer today and he believes the thread is a standard thread. The drill steels are 2 5/8" diameter and the drills are used for exploration use road work subdivisions etc. Core drilling. From the information you have given me at least eliminates NC23. We have tried one bit supplier but he they didn't know the size of thread???

 

[Hush]

I'm on holidays so I don't have my books handy but you might have one of the 'standard' proprietary threads like Hughes, Atlas Bradford, or Hydril. Try getting hold of someone technical at one of the drilling suppliers like Baker Hughes.

 

[kingsland]

If you are looking at a flush joint drill pipe, then I think the thread is a NWJ.

This is common in environmental & DCDMA products.

 

[burgy]

Hi tried emailing drill suppliers for information but no replies as yet. NWJ sounds interesting at least it is one I haven't heard of yet. Does flush joint mean the same as shoulder joint. I do know from past experience the shoulder joint has to be in correct location to the thread otherwise the thread will break off if it carries all the load.

 

[burgy]

Hi Kingsland
surfed up and down the net and found NWJ and it is used with 2 5/8" rods which all looks good. Now I only have to find the dimensions.

 

[kingsland]

Burgy,

Although I have access to most drill pipe thread dimensions, I do not have the NWJ.

I don't know what you are making but there are a few options for your consideration.

1) Have a manufacturer thread the NWJ for you.
2) Purchase a sample piece with NWJ male x female
3) If you plan to do a lot of this work, you can purchase thread gages that would come with specifications.

Some companies that machine this connection are Penndrill (pittsburgh) 800-245-2115, Acker Drill 570-586-2061, to name a couple.

You can reach me at 717-328-4988

Dave

 

[burgy]

Dave
I maintain a small fleet of drills for a customer. Repairing and updating as required. He has recently changed from NW threads to this new thread and he wants me to make the rods subs ect.
I am in the process of manufacturing a new gearbox and modifying the other gearboxs to the tapered thread as well. Hence knowing the exact measurements and type of thread would be very beneifical. As you suggest purchase of thread gauges may be my best way to go. I have samples that I have measured and have made the pin but will need to manufacture a specical tool for the box. Also noted on one of the web sites that the NWJ is a modified Acme thread but the measurements I came up with is 60 degree.
Best regards
Burgy

 

[kingsland]

Borgy,

Have your customer contact the rig manufacturer (if he recently bought a rig with the NWJ) or where he purchased the NWJ tooling. Have him ask for the thread drawings. If he says he has a local shop make special tools for him, I think they will send the drawings.

Meanwhile, I try to get some drawings.

Once you see the thread form, you can probably purchase some form threading tools.

Dave