Apparatus for positioning a workpiece

In a device for positioning and clamping workpieces in three dimensions, which are to be machined, comprising a carrier means carrying three positioning members and clamping means, the improvement wherein each of the positioning members comprises a spherical member having an upper flat plane surface for engaging a workpiece and a spherical seat for each spherical member, each spherical member being capable of limited rotational movement in its seat, at least one of the spherical members having an axial bore and a bolt with a threaded end, said bolt projecting through said axial bore centrally through said upper flat plane surface of said one spherical member, said bolt engaging with its threaded end said carrier means, said bolt forming said clamping means comprising a bolt head having a spherical lower surface facing down, and a washer having a lower flat surface and an aperture surrounded by an upper spherical surface facing up for cooperation with said spherical lower surface of said bolt head, said bolt also projecting through the aperture of said washer and sitting with its spherical lower surface on the upper spherical surface of said washer for clamping a workpiece directly between the upper flat plane surface of said one spherical member and said lower flat surface of said washer, said washer aperture and said axial bore both having a diameter larger than said bolt for a positional adjustment between said clamping means and a workpiece with a hole through which the bolt extends.