Abstract: A chain saw has a chain bar (1) with a nose sprocket (5) over which a saw chain (3) circulates. The sprocket (5) is mounted between two nose cheek plates (53). The interior spacing between the plates corresponds to the thickness of the sprocket. The peripheral area of the sprocket with associated teeth at the bar nose extends outside the cheek plates over at least half the sprocket circumference, such that the saw chain passing over the sprocket goes entirely free from the plates and the rest of the bar. Means are arranged for supplying pressurized lubricant via the bar to the sprocket mounting. The lubricant pressure and the gaps between the side surfaces of the sprocket and the inner faces of the cheek plates are such that in operation lubricant passes out through the gaps.

Abstract: A device for effecting a seal against an underlying surface (5) in conjunction with drilling a hole therein, comprising an inverted cup-shaped member (9,11) whose rim (23) is intended to sealingly abut the underlying surface around the site of the hole (3) to be drilled, and the bottom (11) of which remote from the underlying surface is provided with a hole (27) through which a drill (1) is able to pass in at least substantially sealing fashion in conjunction with a drilling operation. The inverted cup-shaped member includes a tubular, annular element (9), which constitutes a cup-wall element, and a plate-like cover member (11) which forms the bottom. The cover member (11) is removable and therewith exchangeable, and can be mounted on the annular element in an at least substantially sealing fashion in a number of mutually different rotational positions, and is provided with an excentric hole (27) for the drill (1).