The most obvious way to measure the number of twists per unit length of yarn is simply to untwist a known length of the yarn and check visually to see whether the twist has been completely removed. The test instrument that used for to measure the number of twists per unit length of yarn called electronic yarn twist tester . Twist testing methods depends on the specification, accuracy, demanded, from of the sample etc. In general the following points may be followed for getting reliable result. Usually twist is not distributed uniformly along a yarn. Speaking technically, the amount of twist in a materials is inversely proportional to its thickness. This from is ‘twist x weight=constant’’. And for to avoiding having bias in twist measurement, twist should be determined at fixed intervals along the yarn that is 1 yard of distance which is suitable. Withdrawal of yarn over the end of the package adds twist to a yarn, whereas withdrawal from the side of the package does not. ...