66. The plan and the section, Fig. 84, show a smooth-plane. The stock a, when of wood, is usually of beech. In it is an opening, or "throat," b, which receives the iron c; this is held in place by the wedge d. The lower part of the opening is called the mouth; and, as shown by the figure, the shaving passes into the mouth, and out through the throat. The bottom of the plane, which rests upon the work, is called its "face." The iron usually stands at an angle of 45 degrees with the face.

The bench-worker's set of planes comprises a smooth-plane, Fig. 85, which is about 8" in length; a jack-plane, Fig. 86, which is from 12" to 14" in length; a fore-plane, Fig. 87, from 22" to 26" in length; and a jointer, from 28" to 30" in length.

Fig. 83

Fig. 84

Section A B.

Similar purposes are served by the jointer and the fore-plane, the former being unnecessary except for large surfaces that are to be planed with accuracy.

Fig. 85

Fig. 86

Fig. 87

67. The Length of the Plane-Stock determines, in a measure, the straightness of the work. Thus, a smooth-plane, if used on an uneven surface, will, as shown by Fig. 88, rise over elevated portions and settle in hollows, taking its shaving without interruption, and producing no great change in the outline of the surface, while a fore-plane or jointer similarly applied will, as shown by Fig. 89, cut only on the higher parts, and by so doing, produce an even surface.

The stock of a smooth-plane is made short so that, by its use, a surface may be smoothed without incurring the necessity of straightening it.

The fore-plane will smooth as well as the smooth-plane, but not until it has first straightened the surface.

The jack-plane is used for cutting heavy shavings, and its length bears no relation to the character of the work expected of it, but is such as will enable the workman to grasp it easily and firmly.

68. A "Plane-Iron"1 for a wooden plane is of iron overlaid in part with steel. Its cutting edge is maintained in precisely the same way as that of a chisel. See 47 and 48. The angle 1 Known also as "plane-bit." of the cutting wedge, however, for all except the jack-plane may be more acute.

Fig. 88

Fig. 89

69. The outline of the cutting edge, unlike that of the chisel, is never straight, being for the jack-plane slightly curved, as shown by Fig. 90, and for the smooth-plane and fore-plane (also for the jointer) of the form shown by Fig. 91. Being used for heavy work and frequently removing shavings as thick as one-sixteenth of an inch, the jack-plane, if its cutting edge were straight, would produce in the work at each stroke a rectangular channel from which the shaving must be torn as well as cut. Such a shaving would be likely to stick fast in the throat of the plane, or, under most favorable conditions, would require a large amount of force for its removal. A shaving removed by the iron represented by Fig. 90, however, is not rectangular in section, but thick in the middle, tapering gradually to nothing at the edges. This form of iron is best adapted to the removal of a large amount of material at a stroke, but it leaves a succession of grooves upon the work which must be smoothed off by another plane.

.70. The form of the cutting iron in the smooth-plane and the fore-plane, as shown by Fig. 91, is straight throughout the greater portion of its width, and slightly rounded at the corners. The objections urged against the use of such an iron as this in the jack-plane, do not apply to its use in the smooth-plane or the fore-plane, because the jack-plane, to fulfil its office, must remove a heavy shaving; the smooth-plane or the fore-plane, unless the surface upon which it acts is very much narrower than the width of the plane, is required to remove a shaving whose thickness rarely exceeds that of a sheet of paper. The groove caused by the removal of so delicate a shaving, is sufficiently blended with the general surface of the work, by the rounded corners of the iron.

Fig. 90

Fig. 91

71. If a rough board is to be made smooth, or if a considerable amount of material is to be removed to bring a piece of wood to size, most of the surplus stock should be taken off by the jack-plane, after which the smooth-plane should be used to give the surface desired. If the finished surface is to be straight as well as smooth, the fore-plane should follow the jack-plane. It is never necessary to follow the jack-plane with both the smooth-plane and the fore-plane.