Manufacturing holes with hollow bone according to the experiments

Products with large diameter holes (1.5 cm and more) are rarely discovered in the Urals. Among them, a group of non-utilitarian items stands out: shaped hammers, mace, ornamented discs, etc. They are dated to a wide chronological range from the Mesolithic to the Bronze Age. The experiments with hollow drilling during the expedition of S. A. Semenov showed the great complexity of this method. The authors' experiments on hollow bone drilling made it possible to clarify some of Semenov's observations. Through the experiments on drilling of talc, serpentinite, marble and jade, it was planned to identify labor costs for the manufacture of holes with hollow bone, and to reveal various aspects of drilling techniques. The experiments demonstrated the need for a retainer for the drill. It was also found that drilling performance increases markedly if you make several cuts on the cutting edge of the drill. For manufacturing holes with the drill in the tile of talc, serpentinite and marble thickness from 1.5 to 2.5 cm, it took from 1 to 3.5 hours. Jade drill failed. For its drilling, brace - cranked wooden rod with weighting - was used instead of a wooden drill with a crossbar. As a result, a 1.1 cm thick jade tile was drilled in a total of 13 hours and 13 minutes. The experiments showed that the manufacture of the holes of large diameter was preceded by a lot of preparatory work. The obtained results allow the authors to establish with great accuracy what drills and with application of what equipment ancient artifacts in the form of figured hammers, mace, disks and axes were drilled.