The Art of Hand Hammered Copper
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Ancient Egyptian Stoneworking Tools and Methods
Copper coring drills
Large diameter copper tubes (as well as being made of other materials, including brass, tin plate, and soft steel) called coring barrels are used today by amateur lapidists for the coring of rocks and minerals (Sinkankas 1984). These coring barrels are generally thin-walled to reduce as much as possible the volume of rock that needs to be cut away. A coring bit is made by attaching the coring barrel to a wooden dowel, and the coring barrel can often exhibit a groove or gap along the length of the tube to allow new abrasive to more easily reach the cutting surface during use. Today, coring drills can be powered by an electric motor, but they can also be powered by hand, such as with a bow.
In Egypt, a number of carpentry bowdrills have been found that were used by the ancient Egyptians (Fig. 1, Petrie 1974a). The bow was much wider at one end to allow for a handhold, and the drill-stock was made of wood, and sometimes contained a discharge hole to help eject the drill bit (Petrie 1974a, image). The capstone bearing was of wood or hard stone, and had a hole in one end for the insertion of the drill-stock
Many representations in Egyptian art of bowdrill usage is known (Singer et. al. 1954, Aldred 1978, Scarfe 1975, Stocks 1989). The first known depiction of the bowdrill is in the 5th dynasty tomb of Ty at Saqqara, however, the tool must have existed earlier since a number of bored wooden objects exist from the Early Dynastic Period (Nicholson & Shaw 2000).
Examples of other depictions include a carpentry
drill used for boring wood , and a lapidary drill employed in the manufacturing of stone beads .
Hand-powered stone borers were also used by the ancient
Egyptians for the hollowing of stone
vases (Petrie 1974a, 1977, Stocks 1993), and
representations are found in Egyptian art .
No tubular copper barrels or the wooden drill-shaft used for coring of rock have been found in the archeological record from ancient Egypt, or from Mesopotamia and Crete where rock coring was also employed (Stocks 1993, Warren 1969). For the copper barrel, this may be due to the wearing down of the copper tube to lengths that were no longer usable, at which point the remaining copper tube was recycled (Stocks 1993). The use of bow- and hand-powered coring drills as a method of cutting rock is inferred from marks observed on ancient Egyptian stoneworks, finished and unfinished stone objects, and pieces of waste rock.
Both cores and core holes are often
observed to be striated (e.g. an unfinished granodiorite
These striations are observed to be
of the concentric and also spiraling variety Ancient Egyptian coring barrels would have been
made of copper, either cast or
cold-worked until the Middle Kingdom, when bronze tools became more readily available.
Some ancient core holes still contain weathered copper or bronze residue and
rock tailings/abrasive (Lucas and Harris 1962, Stocks 1986). The ancient Egyptians began to make tools of smelted copper by cold-working and casting starting around 3500 BC (Hoffman 1980). The technique of cold-working copper into sheets by hammering existed in early dynastic Egypt, where thin-walled copper vessels have been found (Petrie 1977). The ability of the ancient Egyptians to make copper and bronze tubes, either with sheeting or by casting, is demonstrated in examples of cylindrical vessels (Petrie 1974b) and pipes for plumbing (Wilkinson 2001). The thicknesses of the coring barrels are inferred from tubular slots left on the bottom of stone objects , and were on the order of 1 to 5 mm (Arnold 1991). Casting of copper tubes with 5 mm thick walls can be accomplished with molds of sand