horseshoe shaped filament guide 9 is shown in fig4 the yarn wind up device is disposed below the yarn guide 9 and is indicated only by its essential parts these incldude an adjustable stationary guiding eyelet 10 below which the yarn is moved forth and back by a traversing device which is not shown and indicated by the double arrow a the guiding eyelet 10 forms the apex of the so called traversing triangle the yarn is taken up on a bobbin 11 to form a yarn package 12 the bobbin is driven by a drive roller 13 which engages the package and which is driven by an electric motor not shown the yarn is taken off and taken up at velocities of 3000 6000 meters per minute preferably of 3500 4000 meters per minute the two yarn guides 5 and 9 are of great importance for the application to the yarn of a coating which is as uniform as possible by means of the roller 7 it has been found that the yarn guide 5 has suitably the form shown in fig3 and 5 which is known as a pigtail guide in the art the filament guide is made e g of a ceramic oxide and has a guiding eyelet 6 which has portions that surround the yarn and are convexly curved toward the yarn see also fig5 the pigtail shaped yarn guide prevents the yarn from jumping out of the guide at the beginning of the.