402 



DRILLS AND DRILLING 



[b. a. e. 



L-poiNT OF Stone and Sec- 

 tion OF BORING 



point used is indicated by the form of the 

 perforation. The frequency with which 

 objects are found bored from both sides is 

 proof that the Indian appreciated the ad- 

 vantage of reducing friction. Progress in 

 the elaboration of drills consisted mainly 

 in heightening speed of revolution. 

 If the drill-point be of wood much 

 depends on its hard- 

 ness, for when too 

 h a r d the w o o d 

 grinds the sand to 

 powder, while if it 

 be too soft the grains 

 catch at the base of 

 the cavity and cut 

 away the shaft. 

 Only wood of proper 

 texture holds the sand as in a matrix and 

 enables it to cut to the best advantage. 

 The insides of drill holes show by the 

 character of their striae whether the cut- 

 ting was accomplished by direct pressure 

 or with the aid of sand. 



The simplest form of drill was a straight 

 shaft, varying from a fourth to three- 

 fourths of an inch in diameter and from 

 10 in. to 2 ft in length. 

 This shaft was revolved 

 in alternating directions 

 between the hands, or, 

 when the shaft was held 

 horizontally, it was rolled 

 up and down the thigh 

 with the right harid, the 

 point of the drill being pressed against 

 the object held in the left hand; or at 

 times the object was held between the 

 naked feet while the drill was revolved 

 between the 

 hands. This 

 drill was in use 

 at the time of 

 Col uu) bus and 

 is the only one 

 represented in 

 the Mexican 

 codices (Kings- 

 borough, An- 

 tiq. of Mex., I, 

 pi. 39). With 

 the exception 

 of the strap 

 drill, which 

 was apparently 

 used only in the 

 far N., this is 

 the only form of 

 drill referred to 

 by early Amer- 

 ican writers. 

 The strap drill, used both as a fire drill 

 and as a perforator, is an improvement on 

 the shaft drill, both in the number of its 

 revolutions and in the pressure which 

 may be imparted to the shaft. The shaft 

 is kept in position by means of the head- 



Seotion of Bead 



BICONICAL PERFORA 



, Used by Eskimo of Alaska 



piece of wood, which is held in the teeth. 

 A thong that is wound once round the 

 shaft, one end being held in each hand, 

 is pulled alternately to the right and to 

 the left. The thong was sometimes fur- 

 nished with 

 hand pieces 

 of bone or 

 bear's teeth 

 to give a 

 firmer grip 

 to the strap. 

 This drill, 

 apparently 

 known to the 

 cave ijeople 

 of France, as 

 it certainly 

 was to the 

 early peoples 

 of Greece, 

 Egypt, and 

 India, has 

 been used by 

 the Green- 

 landers from 

 early times and is employed also by the 

 Aleut. To a person using the strap drill 

 the jar to the teeth and head is at first 

 quite severe, but much of the disagree- 

 able sensation disappears with 

 use. 



Closely related to the strap 

 drill, but a great improve- 

 ment over the latter, is the 

 bow drill, which can be re- 

 V o 1 V e d with 

 much greater 

 speed. The head 

 piece of the bow 

 drill is held in 

 position with the 

 I left hand, while 



I the strap is at- 



tached to the 

 two ends of a 

 after wrapping 

 around the shaft, as with the 

 strap drill, is alternately re- 

 volved by a backward and forward mo- 

 tion of the bow. 



The pump drill, still employed in the 

 arts, is said to have been known to the 

 Iroquois and is usedl)y the Pueblo Indi- 

 ans. This drill con- 

 sists of a shaft which 

 passes through a disk 

 of stone, pottery, or 

 wood,andacrosspiece 

 through which the 

 shaftalsoruns;toeach 

 end of the crosspiece 

 is attached a string or 

 buckskin thong hav- 

 ing sufficient play to allow it to cross the 

 top of the shaft and to permit the cross- 

 piece to reach close to the disk. This 



Eskimo Bow Drill 

 Showing Parts 



bow, and 



BOW DRILL With 

 Stone Point, a, 

 Hand-Piece 



USE OF BOW DRIl 



