Pointing machine

A pointing machine is a measuring tool used by sculptors to accurately copy plaster, clay or wax sculpture models into wood or stone.The device is contraption of brass or stainless steel rods and joints, which can be placed into any position and then tightened. It is not actually a machine; its name is derived from the Italian "macchinetta di punta". This tool was first invented by the French sculptor and medallist Nicolas-Marie Gatteaux (1751–1832). [ [http://daf.archivesdefrance.culture.gouv.fr/sdx23/pl/toc.xsp?id=FRDAFAPH_AD075_ph3649&qid=sdx_q0&fmt=tab&idtoc=FRDAFAPH_AD075-pleadetoc&base=fa&n=1&ss=true&as=&ai=| Biography of Gatteaux(French)] ] [ [http://www.edu.augustins.org/pdf/second/sculp/sgen02s.pdf>/ | on Gatteaux' invention of the pointing machine (French)] ]

Technique

To transfer measuring points from a model to a block of stone or wood, the sculptor usually takes three reference points on both model and block, from which to start. By using three of these points a sculpture can be measured accurately, for the three directions of measuring are hereby defined (width, height and depth).

These three measuring points are traditionally used by sculptors to copy a sculpture with callipers, but this is was simplified significantly with the invention of the pointing machine. On these basic points a (usually wooden) T-shaped support is mounted, the "cross". On this crosswood the actual pointing device is attached. By then moving the arms of the tool in such a way that the point of the needle just touches the point to be measured on the model, for instance the nose of a portrait, the sculptor sets the device. Next he takes the whole cross, pointing machine and all, to the block of stone or wood and hooks it up in the identical, corresponding basic points. The needle that defines the measuring point can slide. By subsequently carving or drilling carefully until the needle touches the stop, the sculptor can place his measuring point exactly in the block.By thus copying several dozens or hundreds of points, an accurate copy can be carved. The end result however will still depend on the skill of the sculptor, because these points are only the basis.

The real advantage is the need to measure each point only once, instead of three times with callipers (height, width and depth). Also there is no need to read scales in inches or centimetres, and consequently much less room for error.

Usually the sculptor will make his own crosswood for the statue, as a small statue obviously will need a much smaller one than a life-size one.

Future

Nowadays pointing machines are available in laser versions too. These have the advantage that the needle is not in the way when carving, and that the sculptor hears an audio-signal to warn him when the right depth is reached.

The latest developments are computer guided router systems that scan a model and can produce it in a variety of materials and in any desired size.