Testing showed a roughly 14-inch bow stroke—a comfortable sweep—yielding about four drill rotations each way, versus roughly three-quarters of a rotation per stroke for Denys A. Stocks's hand-powered bow drill. Ropes tried: flax from Egypt, about a month’s shipping, at one and one-quarter inches, plus tarred bank line sizes 48 and 60. Bank line wins for a field kit: no stretch and ends that seal with flame.
Rope and bow-stroke tests: Egyptian flax versus tarred bank line
Key facts
- The bow is cut to a measured stroke length of about 14 inches, chosen as a comfortable sweep for the operator.
- The setup yields about four drill rotations per stroke in each direction; the presenter estimates Denys A. Stocks's hand-powered bow drill produced about three-quarters of a rotation each way.
- Rope options tested: pure flax rope ordered from Egypt in about a month of shipping, in roughly one-inch and one-quarter-inch diameters, and tarred bank line in sizes number 48 and number 60.
- Bank line is preferred for field or survival use because it does not stretch and its ends can be sealed with flame.
- A small analog gauge was mounted on the bow drill to measure spin speed and reduce the need to show all testing on camera.
Sources
NOVA Online | Mysteries of the Nile | E-Mail: March 16, 1999pbs.org
Response from Denys Stocks, Ancient Egyptian Technologist: In my opinion, the evidence all suggests that the Egyptians were able to drill ...
Tag: bow drillveronicasart.com
While Christopher Dunn looks at a granite core and sees machine feed rates, Denys Stocks looks at the same core and sees the natural behavior of sand grains ...
Figure 11 from Arcus in Horace, Carm. 3. 26. 7semanticscholar.org
Fig. 11. Drill and stock of a bow drill from Hawara, Egypt. Roman period. University College, London. Repr. from: W. M. F. Petrie, - "Arcus in Horace, Carm.
Experiments in Egyptian Archaeology: Stoneworking ...books.google.com
In this fresh and engaging volume, Denys A. Stocks examines the archaeological and pictorial evidence for masonry in ancient Egypt.
Mysteries of the Nile | On an Anthill in Aswan (2)pbs.org
Denys Stocks, middle, bears down on a large copper drill bit as Hopkins and Mark Lehner operate the bow drill. While other members of the team have busied ...
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