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Experiments in Egyptian Archaeology: Stoneworking Technology in Ancient Egypt
116. Eight copper tubes, one bronze tube, a copper saw and a bronze saw were tested upon the soft and hard limestones, calcite, hard sandstone (coarse-grained), blue granite (close-grained), rose granite (coarse-grained) and diorite.48 The specific gravities of the stones are contained in Table 4.4. A mild steel saw was used to test cut the granite and the hard limestone.49 

116. The experimental sawing of the granite with the low carbon content (less than 0.30% carbon) annealed mild steel saw (VPN 131), similar to annealed wrought iron’s characteristics, indicated that iron saws effectively could have cut through this stone. The steel saw’s rate of cutting was lower than the copper and bronze (annealed hardnesses of VPN 42 and 75 respectively) saws’ cutting rates. The tests suggested that an iron saw needed to be as soft as possible, allowing the angular quartz crystals to embed themselves more easily into the metal, thus increasing its efficiency as a cutting tool. However, the saw required a pressure of 3 kg/cm2 in order to obtain an optimum sawing rate.

118. The copper and bronze saw cutting results closely matched the tubular drilling results for these two metals. It will be noticed, in comparing the results in Table 4.5 with the results contained in Tables 4.2 and 4.3, that the harder steel cuts less efficiently than the softer copper and bronze tools: for the purposes of testing, cast copper and bronze tubes and saws were left to cool slowly, which fully annealed them. The beaten copper sheets were annealed before bending them into tubes.