Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 135

For boring holes across the grain with the centre bit, hold the board firmly on a piece of waste wood, then bore right through into the latter; or bore from the face of the board until just the point of the bit appears at the other side; then reverse the board, place the point in the hole, and finish boring. In boring, see that the chips rise out of the hole; when they do not, remove the bit and shake out the pieces, or the chips may wedge against the tool, and the bit will run to one side or be broken. Boring holes into the end grain of a piece of timber with a centre bit is an operation that sometimes gives trouble. In some woods little pieces of detached material persistently get wedged between the bit and the side of the hole, as at P (Fig. 398). Twist bits are best for this class of work, but when a series of exceptionally clean holes is required in the end grain, and when there is not sufficient room to take the brace and a long twist bit, the specially designed centre bit shown by Fig. 400 will give excellent results. It is made of 1/2-in. steel beaten out, turned up, and filed to the proper shape. The method of holding the brace when boring vertically is shown by Fig. 401, and when boring horizontally by Fig. 402. The use of a hand drill, which for some purposes may be preferred to the ordinary brace, is illustrated clearly by Figs. 403 and 404, the former showing horizontal boring, and the latter vertical boring. A method of getting a true horizontal hole is shown by Fig. 405, a shaped support for the bit being held in the bench vice or in some other manner.

Fig. 403.—Horizontal Boring with Hand Drill.

Fig. 404.—Vertical Boring with Hand Drill.