Boring

Act or operation of cutting a circular hole with a drill, auger, or other instrument. -A hole caused by boring. -pl. Fragments of wood, chips, ., after a hole has been bored. M N (Hydraulics.) The operation of piercing the earth for the purpose of ascertaining the nature of the subjacent strata, or of bringing to the surface any underground springs. A great variety of tools are employed for this purpose, such as, augers , jumpers , misers, ball and socket valves , according to the strata traversed. - B. has been well applied for the purposes of fixing the posts of electric telegraphs: for the tying down bolts of suspension bridges, and for the sinking tubes now used for the foundations of buildings to be erected in running water, . Bor'ing-machine, n . (Mech.) A machine for the boring of holes in metal plates for making attachments. It is effected by means of drills driven by machinery, as shown in Fig . 393. The drill is inserted in the end of a vertical spindle, P, which revolves in a fixed frame, and is driven by the bevel-wheel G. The metal to be bored is placed on a table or other support below the drill; and the up-and-down motion, or end-pre ure and off-action, of the drill is effected by the hand-gear, O, N, turning the screw M; which being coupled to the top of the spindle at L, pre es it down or raises it, according to the way it is turned. The spindle slides vertically to the collar forming the axis of the bevel-wheel, but is carried around with it by means of the pin I, which projects into a groove seen at J.