UNC THREAD VS NPT TREAD.

In oil and gas industry, different types of thread connections are usually used to ensure the leak proof joint.
one of the most common thread connection is UNC & NPT.

• UN thread has two types. UNC & UNF

UNC means Unified coarse thread, UNF means Unified fine thread. both are same only difference is in their pitch. UNF has less pitch thread compare to UNC.

• NPT Thread

NPT means National Pipe Tapered. this is most common for high pressure applications and where leak proof solution is more important. 

the leak and tightening of the two suraface is done with the help of wedge action.