The invention provides textile cores having improved start-up grooves. In a preferred embodiment the start-up groove has a generally V shaped cross-section and at least one longitudinal portion of the groove, preferably the trailing portion of the groove, has at least one compound angle sidewall defined...http://www.google.es/patents/US5495087?utm_source=gb-gplus-sharePatente US5495087 - Grooving blade for textile core
