The transverse friction coefficient of a yarn sliding on a surface is much more difficult to measure than its lengthwise coefficient. A method based on the transverse sliding of the yarn on the cylindrical balloon limiter of a two-for-one twister is proposed to measure this coefficient. A simple yarn ballooning apparatus based on a hollow spindle was built and tested. A top picture of the cylindrically constrained yarn balloon is taken and the final yarn angle is measured. This angle can be theoretically correlated to the other easily measured parameters of the simplified balloon and the desired transverse friction coefficient. This method was experimentally verified and found to be both practical and highly accurate.
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