44. Thru Boring.
—To avoid splitting the wood around the edge of the hole when it is desired to make a hole entirely thru a piece, bore from the face side until the point of the spur can be felt on the back. Then reverse the position of the board and, inserting the point of the spur in the hole just made, finish the boring from the back side. The bit must be held perpendicular to the surface while boring from the second side, as well as the first, or some of the edge of the hole will be broken from the first side as the bit is forced thru.
45. Boring to Depth.
—When it is desired to bore to a given depth, turn the crank of the brace until the lips of the auger are just ready to cut the surface. With the rule, measure the distance from the surface of the piece to the grip of the brace. [Fig. 85]. The brace may then be turned until this distance is diminished by the amount which represents the desired depth of the hole.
Fig. 85.
Fig. 86.
Where many holes of the same depth are to be bored much time will be saved by cutting a block the length of the exposed part of the bit when the hole is to the required depth. This can be placed beside the bit so that the grip will strike it. [Fig. 86].