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Pipe Threads

Pipe Threads

AUTHOR : _ _ Date : 4/18/2013 1:48:20 AM

When we talk about pipe fittings, it means that fittings are used to connect two or more pipes in two ways—either by threads or by welding. While metal pipes are threaded,  a threaded pipe has screw-threaded ends for assembly or they screw together to connect.

For pipe thread sizes, “½–14 NPT” identifies a pipe thread with a nominal inside diameter of ½ inch and 14 threads to the inch and these threads are made according to the NPT standard. The pipe has a left hand thread if “LH” is added. The pipe thread standards followed in US are:
  • NPT: American Standard Pipe Taper Thread
  • NPSC: American Standard Straight Coupling Pipe Thread
  • NPTR: American Standard Taper Railing Pipe Thread
  • NPSM: American Standard Straight Mechanical Pipe Thread
  • NPSL: American Standard Straight Locknut Pipe Thread

The word “taper” mentioned above refers to the difference between many pipe threads and those on bolts and screws. Pipe threads not only a make mechanical joint but also a leak proof one. To do this, the threads become shallower the farther they are from the end of the fitting or the pipe. The bottoms of the threads taper. The taper is 1/16 inch in an inch.

Pipe Threads

Because of the taper, a pipe can only screw into a pipe fitting a little distance before it jams. The standard represents this distance, the effective thread. The standard also represents another distance, the engagement, which is the distance the pipe can be screwed in by hand, without much effort. For workers, it is more easy to know how many turns to make by hand or with a wrench. 

Types of threads

Various threads available in pipe and pipe fittings are as follows: 
1. Male Threads
In male threads, the threads of pipe fittings are on the outside. Here, tapered pipe threads like NPT, BSPT etc. are used sealing without gaskets.
2. Female Threads
In female threads, the threads are on the inside. Here too, like male threads, tapered pipe threads are used for sealing. 
3. Plain End
This is used to connect or insert into the bell end of the connecting pipe.
4. Socket
This represents the end length of increased diameter into which a pipe end can be fitted.
5. Flange
Flanges are used to connect fitting, via bolting or welding. There are basically two types of flanges, circular and square.

Check all kinds of pipe fittings

1. Elbow:
45 degree elbow
45D CS butt weld elbow    45D SS butt weld elbow   45D socket weld elbow   45D threaded elbow
90 degree elbow  
90D CS butt weld elbow    90D SS butt weld elbow   90D socket weld elbow
   90D threaded elbow     street elbow
180 degree elbow  
180D CS butt weld elbow      180D SS butt weld elbow

2. Tee:
CS butt weld straight tee   CS butt weld reducing tee   SS butt weld straight tee  SS butt weld reducing tee  socket weld tee   threaded tee
   Lateral tee:
CS butt weld lateral tee   SS butt weld lateral tee   socket weld lateral tee   threaded lateral tee

3. Cross:
CS butt weld straight cross   CS butt weld reducing cross   SS butt weld straight cross   SS butt weld reducing cross   socket weld cross   threaded cross

4. Reducer:
CS concentric reducer   CS eccentric reducer  SS concentric reducer   SS eccentric reducer

5. Cap:
CS butt weld cap   SS butt weld cap   socket weld cap   threaded cap

6. Stub end:
CS stub end   SS stub end

7. Coupling:
socket weld full coupling   socket weld half coupling   threaded full coupling   threaded half coupling

8. Union:
socket weld union   threaded union

9. Socket insert:
A  B

10. Plug:
hex head plug   square head plug   round head plug

11. Bushing:
hex head bushing   flush bushing 

12. Nipple: 
TBE   PBE   TOE&POE   hex nipple

13. Swaged nipple:
concentric swage nipple   eccentric swage nipple

14. Flange:
Orifice flange   lap joint flange   threaded flange   socket weld flange   weld neck flange   blind flange   slip on flange   long weld neck flange   plate flange   large diameter flange   spectacle blind   square flange   

15. Outolet:
weldolet   socketolet   threadolet  laterolet  coupolet  elolet   nipoflange   nipolet

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