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Wood-Working Machines

edge, bit, figure, stock, planing, iron and plane

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In wood-working machinery there are ten principal classes of opera tions: (1) Chopping, riving or splitting; (2) sawing; (3) planing or shav ing; (4) incising; (5) boring; (6) routing; (7) turning; (8) bending; (9) polishing, and (io) compressing.

Choppinc and or Sp/filing arc very simple operations, effected with primitive tools, and generally without the aid of machinery, although in making kindling wood and square-sectioned match-splints, power-driven splitting-machines are used. The axe, the hatchet, and the rail-splitter's wedge are familiar to all and need no illustration. Their work may pro duce chips or it may produce no waste as in ordinary splitting.

Serving is referred to in great fulness of detail, under the head of Saws (p. 65, el seq.); and saws are employed in tenoning-machines, referred to later on (p. 86). The waste resulting from the use of saws is in the form of saw-dust, small chips, or saw-dust and blocks.

Planing and Tools and Alachines, with which may be included those for moulding and those for "matching" (or tonguing and grooving), pare or slice off the material from the surface, usually working lengthwise of the grain, commencing at one end of a piece and working toward the other. The waste from their work is in the form of long shavings or of short shaving-like chips. Hand-planes, spoke-shaves, and planing and matching machines are employed here. The paring-chisel and the gouge, also used in such actions, work lengthwise of the material and remove shavings and chips, the chisel having its cutting edge straight and the gouge curved. Hand-planes are shown in Figures 2 to 13 (pi. 13); a spoke-shave in Figure 28; paring-chisels in Figures 29 and 3o, and gouges in Figures 31 and 32. Planing, moulding, and matching machines re ceive full attention later on. The plane is a tool for working the sur faces of solid bodies by being carried over them to and fro with straight strokes. In hand-planes the edge is prevented from penetrating too deeply into the surface of the material to be worked upon by being contained in a fastening- or "stock," which limits its protrusion. In planing-machines the rectilinear motion of the piece to be planed or that of the tool is secured by special guides. The application of the hand-plane is limited to soft materials (wood, soft metals), while for planing hard materials (as iron) power-driven machines are generally used.

Wood 2 to 13 show the form and arrangement of the most important hand-planes. They have either single " irons " or bits (figs. 2, 3, 5) or double bits (fig-. 4). Upon the front of the cut ting-bit in Figure 4, the edge of which detaches the shaving, lies a shift able top-iron or breaker, whose lower edge is set close to the edge of the cutting-bit. The shaving, ascending before the bit, is partially broken by this breaker, thus preventing "tearing" in case the fibres should run unfavorably. For this reason planes with double irons (p. 13, fig. 7) are especially suitable for finishing surfaces. Figure 2 shows the bit of a jack-plane which serves for roughing. The edge of the iron is convex, so that the resulting shavings will be thickest in the middle of their width. Figure 3 shows the bit of a smoothing-plane, which is distin guished by a straight edge. Figure 5 represents the bit of a plough (grooving-plane), in which the edge corresponds to, the profile of any moulding. The iron is secured by a wooden wedge driven tightly in front of the plane-iron or forced in by a screw or lever. In the ordinary planes (figs. 6-8) for working surfaces free all around, the edge of the iron does not extend the entire width of the stock, which renders it impossible to continue the smoothing to the innermost edge of a re-entrant angle; to do this the plane-stock is given the form shown in Figure 9 (rebate plane), and the lower portion of the bit may have a slightly greater width than that of the stock. For smoothing a surface bounded all around by a plane ascending at a right angle—for example, a mortise —a router-plane (fig. 1o) is used. In this form the iron stands free all around, the peculiarly shaped stock being guided upon a surface parallel to that to be smoothed. For smoothing the sides of a mortise with rectangular cross-section the bit as well as the cross-section of stock receives a T-shape, the plane being known as a T-rebate (or rabbit) plane (fig. 12). The planes shown in Figures II and 13 serve for grooving level and concave surfaces. In the stock are two scoring-cutters, which precede the plane-iron and cut the fibres to be detached by the latter.

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