registry with each other and to maintain the assembled plates and their associated end blocks 50 and 51 in a tight fitting relationship thus e g the intermediate plates and the end blocks can possess a series of evenly spaced apart apertures 29 which in the assembled yarn interlacer provide thruways accommodating terminallythreaded aligning bolts or rods 56 the bolts 56 extend beyond each end of the apparatus a sufficient distance to receive locking nuts 57 the overall dimensions of the intermediate plates and end blocks can vary considerably according to the dimensions suitable for the process where the invention is used in general the plates and end blocks may have the same or substantially the same planar dimensions e g from about 0 75 to about 1 5 inches in width and about 0 75 to about 1 5 in height the plates can possess the same or different thicknesses e g from about 0 015 to about 0 1 inches and the overall length of the fully assembled yarn interlacer can vary in the usual case from about 0 75 to about 2 0 inches with a diameter ranging from about 0 1 to 0 3 inches end block 50 possesses ducts 52 and 53 see fig4 for receiving fluid inlet conduits 54 and 55 see fig3 respectively both end blocks possess passageways which cooperate with passageways 22 in intermediate plates 20 to form a single longitudinal yarn passageway it should be understood that the yarn passageway 22 in end blocks 50 and 51 may.