Abstract: A knot hole beam, for instance a warp beam for looms, for winding-up yarns or the like, comprising a winding tube or cylinder provided at its periphery with knot holes, each knot hole possessing an insertion bore serving for the insertion of a bundle of tied together or knotted yarn or thread ends and at least one, therewith merging knot arresting opening of narrower shape than the insertion bore. Between the insertion bore and the knot arresting opening there is provided at least at one side of the knot hole edges an arresting projection for the inserted knot. Such arresting projection protrudes towards a line which is axially parallel to the lengthwise axis of the tube and extends through the center of the insertion bore. The arresting projection is situated closer to such axially parallel line than an outer peripheral portion of the knot arresting opening which is situated furthest therefrom.