auger (ager)

[Initial n has been lost, as in adder, umpire, etc.; early mod. E. also augre, aug or, etc., and, with or i ger at or, nauger, naugor, earlier IMG:content-1394.png:[blocks in formation] those bored by a bit or gimlet. It consists of an iron shank ending in a steel bit, and a handle placed at right angles with the shank. The augers formerly made with a straight channel or groove are called pod- augers; augers of the modern form, with spiral channels, are called screw - augers. The ordinary screw-auger is forged as a paralleled blade of steel, which is twisted while red-hot. The end terminates in a worm, by which the auger is gradually drawn into the work, like the gimlet. Another form is that of a cylindrical shaft, around which is brazed a single fin or rib, the end being made into a worm, and immediately behind the worm a small diametrical mortise is formed for the reception of a detached cutter, which exactly resembles the chisel-edge of the center-bit. Expanding augers have cutters susceptible of radial adjustment for boring holes of different sizes. In the slotting - auger, used for channels, mortises, etc., the cutting lips are upon the side of the auger as well as at the end, and the piece to be grooved is fed against them laterally. Mortises are cut by causing the auger to penetrate to the proper depth, and then feeding the work laterally to the required length. The two rounded ends of the mortise are then squared with a Slotting Auger. chisel. The square -hole auger is an auger revolving within a rectangular tube or boring, whose lower edge is sharpened to cut away the remaining substance of the square circumscribing the round hole which the auger bores a little in ad vance. 2. An instrument for boring the soil. Such an instrument used in setting posts is called a post - hole auger, and one for ascertaining the nature of the subsoil, the presence or absence of water, etc., is called specifically earth- boring auger. Augers for the latter use are of various kinds, but they all consist of three parts, namely: a handle by which two or more men can work the instrument; the bit, mouth, or cutting piece; and rods for connecting the handle with the bit or cutting piece. - Annular auger. See annular. an Post-hole Auger. Earth -boring Augers.