Abstract: A bit holder is provided which includes a body having a cavity formed with an upper portion and a lower portion, separated by a ridge-like protuberance which has a cross sectional profile smaller than that of the upper portion and the lower portion. The ridge-like protuberance is formed on each sidewall of the cavity to form an interference fit. A method of manufacture includes the use of a punch to force material from the upper portion downwards towards the lower portion of the cavity to form the ridge-like protuberance.

Abstract: A bit holder is provided which includes a body having a cavity formed with an upper portion and a lower portion, separated by a ridge-like protuberance which has a cross sectional profile smaller than that of the upper portion and the lower portion. The ridge-like protuberance is formed on each sidewall of the cavity to form an interference fit. A method of manufacture includes the use of a punch to force material from the upper portion downwards towards the lower portion of the cavity to form the ridge-like protuberance.

Abstract: A stronger screwdriver blade is disclosed which is particularly effective for driving round-headed screws. The screwdriver blade has an elongate shank with a tapered end extending from the shank and terminating in a tip. The tip has a straight edge perpendicular to the shank and has a predetermined length and thickness, with side edges extending back toward the shank from ends of the end edge. The tip has substantially parallel, planar sides extending back toward the shank from the end edge to inner edges which, at the side edges, are spaced a distance from the end edge which is approximately equal to the thickness of the end edge. The inner edges are curved with the planar sides being from one and one-half to three and one-half times as wide at central portions as at end portions. From the inner edges, opposite side surfaces of the tapered end extend abruptly outwardly in a direction toward the shank so that the blade tip is thicker at high stress areas thereof.

Abstract: A cigarette filter rod element including an axially extending barrier tube of micro-fine fibres with a diameter of between 0.5 and 10 microns and located so that at least part of the gas flow passes through the wall of said barrier tube.