Abstract: A torque transmitting device for insertion into a bore in a workpiece, the device being, for example, a stud extractor, has slots spaced around the periphery of a shaft and extending longitudinally of the shaft, each of the slots having a bottom surface inclined towards the periphery of the shaft, and a workpiece-engaging blade in each of the slots. Each blade is formed with an outer cutting edge for biting engagement with the wall of the bore and has, at one of its end, a radially outwardly extending projection. An annular blade retainer extends around the blades and the shaft and engages the projections for retaining the blades on the shaft, the retainer being displaceable along the shaft. A nut in threaded engagement with the shaft serves for longitudinally displacing the blades on rotation of the nut relative to the shaft.