Abstract: In order to achieve a secure join between the base and the covering of a disc-shaped tool, e.g. a circular saw, provided with a vibration-reducing structure at least on one side and to prevent the covering of the structure from separating from the base, an edge region of the covering extending into a groove in the base is joined elastically to the base at least in part on the rear and/or end surface by at least one holding element.

Abstract: The article, such as a circular saw tool or a gear wheel, has a visco-elastic synthetic-resin damping layer between, on the one hand, a portion of the body of the article which is integral with, or securely attached to, a work region adapted to interact with another article, and, on the other hand, a counter-element which extends parallel thereto. The damping layer is arranged in the interior of the article in a region covered by an outer member integral with or securely connected to the body. The parts between which the damping layer lies are connected together by the damping layer in a manner which permits shear stresses to occur in the damping layer.

Abstract: The article, such as a circular saw tool or a gear wheel, has a visco-elastic synthetic-resin damping layer between, on the one hand, a portion of the body of the article which is integral with, or securely attached to, a work region adapted to interact with another article, and, on the other hand, a counter-element which extends parallel thereto. The damping layer is arranged in the interior of the article in a region covered by an outer member integral with or securely connected to the body. The parts between which the damping layer lies are connected together by the damping layer in a manner which permits shear stresses to occur in the damping layer.

Abstract: A blade with teeth whose spacing varies around the periphery has, on at least one side, a cover element and an intermediate visco-elastic layer, in order to reduce noise. A holding element fixed to a support ring holds the cover element on the blade independently of the intermediate layer and allows the layer to perform a damping function subject to thrusting stresses.

Abstract: The invention provides a method of examining roughness of a surface of a workpiece, comprising: scanning said surface by means of a resiliently mounted support element during linear relative movement between a sensing element and said surface whereby self-oscillations are generated at the sensing element or at parts in connection therewith by unevennesses of said surface; receiving said self-oscillations; and determining a value which corresponds at least approximately to the magnitude of the amplitudes of the oscillations, said value being a criterion of roughness of said surface. The invention also provides apparatus for examining roughness of a surface of a workpiece, comprising: a holder; a sensing element; a support for the sensing element; the sensing element being movably supported against a yielding resistance by the holder; and a receiver system for oscillations and adapted to deliver electrical signals at its output, the sensing element or the support therefor being connected with the receiver.

Abstract: Circular saw tool, with a single-ply or multi-ply disc-shaped saw blade and teeth distributed over the circumference thereof, the saw blade being provided on each side with a bonded covering.