INTRODUCTION The purpose of this tool is to open up a hole by the physical removal of material1 and it operates by ... The rotary motion can be provided from two distinct sources a manual twisting or mechanically-assisted drilling. Some modern types are illustrated in Fig. 33. In the first class, the Bronze Age craftsman had the awl, inherited from his Neolithic predecessors: an extremely simple, more oranbsp;...
|Author||:||R. D. G. Evely|