Abrasion - Forage tubulaire et Scie en Cuivre : Exp. d'Assouan

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Référence - Mégalithe

 


Livre


 

Experiments in Egyptian Archaeology: Stoneworking Technology in Ancient Egypt
129. While the small-scale Manchester tests established the initial sawing and drilling data, it is now instructive to see how the large-scale tests proceeded in Aswan. In March 1999, an opportunity arose to saw and drill the rose granite in a quarry located on the edge of the southern Egyptian town of Aswan. Several Egyptian quarry workers operated a 1.8 m-long copper saw and an 8 cm-diameter copper drill-tube, which was taken to Egypt with its driving bow. These sawing and drilling experiments were undertaken to test two theoretical propositions59: that two- and three-worker teams were required to drive large ancient saws (Figure 4.19) and tubular drills (Figure 4.20) respectively. The saw and the drill-tube were tested upon the rose granite under realistic ancient conditions, and the results compared with those obtained from the previous experiments conducted with the much smaller reconstructed copper saws and drills in Manchester.60 Each Aswan tool used locally obtained sand as the cutting abrasive.

The unused 1.8 m-long copper saw blade, stood on its edge, measured 15 cm in depth, 6 mm in thickness and weighed 14.5 kg. The quarry workers had previously, and unnecessarily, fitted a heavy wooden frame to this saw blade, as well as notching it numerous times along the cutting edge with an electric abrasive wheel; no doubt, they understandably were influenced by modern working practices. Nevertheless, for comparison with a completely flat edge acting on dry sand abrasive, it was decided to test the notched edge with very wet, fluid sand along a granite block’s width of 75 cm, its surface initially pounded flat along the line of sawing.

130. Two workers pushed and pulled the saw from opposite sides of the block. The blade rocked from side to side during each forward and backward movement, creating a V-shaped slot.61 At a depth of 8 cm, the V’s cross-sectional shape measured 2.5 cm at the top and 6 mm at the bottom, each side angled at 7° to the vertical. This V-shaped slot is similar to the two partially sawn slots seen in Hordjedef’s rose granite sarcophagus in the Cairo Museum, and saw-slots cut into a basalt pavement block near Khufu’s pyramid at Giza.62 The laterally curved bottoms of these slots are a further consequence of the rocking action of the ancient saw blade, which itself would have assumed a laterally curved shape along its cutting edge. These phenomena occurred in the wet and the dry sand-sawing experiments.

131. In Table 4.3, the three ratios expressing the volumes, weights and depths of the copper worn off the saw (separately with the wet and dry sand abrasive) to the volumes, weights and depths of the sawn granite are recorded as 1, 2 and 3 respectively. The ratios obtained from sawing with the flat-edged blade and dry sand show an improvement to the ratios achieved with the notched saw and wet sand.

 


Mégalithe


 

Exp d'Assouan de 1999 : Scie de 14.5kg

 

Exp d'Assouan de 1999 : Tube de 8cm