Abstract: The holder comprises a pair of clamp members fitted with recesses to grasp a linear segment of a tool. These members are pivotally secured together on one side and secured by machine screws or the like near the opposite side. The lower clamp member is fastened in such a way that the upper clamp member may undergo pivotal movement relative to the fastened lower clamp member when the machine screws or the like are loosened. Particularly desirable combinations and positioning of parts for effecting such fastening are described. Also described are (i) a particularly desirable interlocking construction for pivotally securing the clamp members together along one side without actually fastening them together along that side, and (ii) other preferred features which may be employed in the device.

Abstract: The assembly described comprises a shaft mountable in the tailstock and upon the forward portion of which is rotatably supported a hub. One of a plurality of interchangeable frustoconically shaped work centering support members which differ from each other in external diameter and which are individually frictionally supportable on the hub to accommodate variously sized hollow workpieces is mounted on the hub. The assembly is lighter in weight and has better service characteristics than prior art devices.