The auger-bit, Fig. 68, is used for all ordinary work. The size of hole a bit will bore can be told by the number on its tang, which number is the numerator of a fraction whose denominator is 16 on auger-bits and 32 on drill bits. Sometimes the whole fraction is stamped on the shank or the tang.
Fig. 66. Horizontal Boring; First Position.
Fig. 67. Horizontal Boring; Second Position.
In boring, stand so as to sight the brace and bit from two directions at right angles one to the other, Figs. 66, 67, 69 and 70, swinging the upper part of the body from one position to the other as the boring proceeds.
Fig. 68. Auger-bit.
Fig. 69. Vertical Boring; First Position.
Fig. 70. Vertical Boring; Second Position.
In boring to depth, a rule may be placed as in Fig. 71 as the lips begin to cut, and the boring continued until the measurement at the grip has diminished an amount equal to that desired for the depth of hole.
Fig. 71. Measuring Depth.
Where it is desired to bore entirely through a board, it is best to bore from the first side until the spur shows on the back, then reverse the piece and finish the boring from the reverse side, otherwise the nibs might split the wood on the reverse surface.