The friction and cohesion forces are some of the most important parameters that affect the yarn spinnability and tenacity. A new and simply device is carried out in order to quantify the friction and cohesion forces during a quasi-static fiber slippage in a sliver. This device is composed of two identical little carriages; one of them is fixed whereas the second is moving on a linear guide. A piece of sliver is put down in carriage channel in the jointed position. The sliver is compressed with the upper carriage sides where two identical weights are loaded. A digital video camera records what is happening between the two clamps during the traction test. The results show that the force-displacement diagrams are very similar. At the beginning the force increases almost linearly with displacement, then it remains constant and, at a given displacement, where there are no more fiber clamped by both carriages simultaneously, the force starts to decrease linearly. The parameters of this curve seem to be related to the inter-fiber friction and cohesion force.