Pointing machine

A puncturing device is a measuring device for making copies in sculpture.

The puncturing device is based on the stereometric law that any three fixed points in space, a fourth point may be defined by distance measurements.

Function

These three fixed points must be fixed at the beginning of the work on both the model and the workpiece. In or on these points, the so-called puncturing cross is hung or mounted. The puncturing cross a metal rod having a plurality of lockable ball joints is fixed so that as the entire surfaces of the model can be achieved. At the end of the boom, there is a moveable needle, which is set up for scanning a point on the model perpendicular to the surface. Now the rider is so fixated on the needle that it rests against the stop of the rod. The point is marked with a pencil or similar. Thereafter, the needle is retracted inside a parallel guide linkage and reacted in the puncturing device from the model of the workpiece. After pre Push the needle to the workpiece, the sculptor can read by measuring the distance between the stop and rider, how much material at each step needs to be machined off. By alternately Previous work of the workpiece and measuring approach by pushing the needle puncturing the sculptor slowly approaches the desired point. At the end of a small depression is elaborated in order to eliminate errors in the angle between puncturing needle and the surface to be created. Also for the point on the workpiece is highlighted. Depending on the accuracy of the copy to be created, the points are more or less set tight. Only in the final processing, the points are connected to each other and creates the actual surface of the sculpture.

History

The invention of the puncturing device in its current form is both the French sculptor Nicolas- Marie Gatteaux (1751-1832) and the Englishman John Bacon the Elder - attributed (1740, 1799). Other measurement methods with cubic or cylindrical coordinate system based on a similar principle and were already centuries earlier in use. Leon Battista Alberti in his treatise De Statua shows (before 1435 ) a cylindrically constructed measuring device, which he calls Definitory. The advantage of such an apparatus is that it can also be used to enlarge or shrink. Overall, however, the use of solders and laths was cumbersome, time consuming and imprecise.

The puncturing unit with sliding needle was first used in studio Antonio Canovas for enhanced application and spread in the 19th century in general. In the wood and stone sculpture, it was henceforth an indispensable tool: In the workshop operation of the master rough preliminary work could now be delegated to a journeyman, without running the risk that the sculpture is corrupted.

During the 20th century the use of the puncturing device took off again, however, the immediate of the creative process moved more to the interest of the artists (direct carving ) as the meticulous copying of a model.