The friction and cohesion forces are some of the most important parameters that affect the yarn spinnability and tenacity. A new and simple device is carried and developed out in order to quantify the friction forces during a quasi-static fiber slippage in a sliver under controlled normal pressure. The force-displacement curves  are analyzed in order to check out the parameters which characterize the friction force during inter-fiber slippage. If the force and the load are normalized with respect to the sliver count, the frictional behavior of the fibers can be described by only two coefficients which can be used to distinguish different cottons.