Boring
a process in mechanical and engineering operations, variously performed according to the medium dealt with. For making small holes in soft woods and like substances, awls are employed, which merely cut and displace a portion of the yielding material. In boring hard woods and large holes , carpenters use gimlets, augers, and the brace and bits, which all cut and scoop out the material. In the jewelry and small metal industries, hand drills, which consist of a spindle with steel bits, to which reciprocating rotation is given, are the implements for piercing small holes. The boring of holes in metal plates is effected by means of drills driven by machinery.
As applied to the earth and to rocks, boring embraces two classes of operations -boring of shot holes for blasting, and the sin sinking of bores in prospecting for minerals, and in forming wells for water, salt brine, and mineral oils. Blast holes in rocks are made from one to twosometimes more-inches in diameter, and may pierce to the depth of 9 feet. Such holes are most simply made in hard rock by a steel-pointed drill, struck by a hammer, and turned partly round after each blow to make the hole cylindrical.
BORIS III., King of Bulgaria; born Jan. 30, 1894. He was the eldest son of King Ferdinand, and succeeded to the throne when the latter abdicated and fled to Vienna, Oct. 4, 1918.