NPT can completely twist exactly?

The NPT is common thread on the foreign market, are often used for bimetallic thermometer, the NPT can totally twist exactly? Instrument answer: NPT is taper sealing thread, there is a screw or limit, the limit and then twist will destroy the thread, so can't be completely twist exactly. NPT thread is an American standard taper pipe threads 60 degrees, can be divided into general sealing of cylindrical pipe thread and general sealing tapered pipe thread, cooperate way by & other; Cone/cone & throughout; Cooperate, & other; Column/cone & throughout; To cooperate. NPT cooperate way: cylindrical internal thread and cone of external thread & other Column/cone & throughout; Cooperate; Of taper thread and taper thread within & other Cone/cone & throughout; To cooperate. NPT threads used in the joint of bimetallic thermometer, bimetallic thermometer is a kind of measurement in the field of low temperature test instrument. Bimetallic thermometer can be directly measured in the process of various production - 80 ℃ ~ + 500 ℃ within the scope of liquid, steam and gas medium temperature. Bimetallic thermometer is a round shape into threaded heat bimetallic strip as thermal devices, and put it in a protective sleeve tube, one end is fixed, known as the fixed end, the other end of the connection on a thin shaft, called the free end. Spool at the free end is equipped with a pointer. When the temperature changes, the resulting thermal devices the free end of the rotation, drive the thin axis from the Angle of the pointer changes, corresponding temperature indicator on the dial.