Planes are so necessary for all kinds of work. that any who intend to work in wood, should understand the struc ture, and the manner of using them. The jack plane is used for taking off the rough and prominent parts from the surface of the wood, and reducing it nearly to the intended thickness, in coarse shavings, or slices. The stock of this plane is about seventeen inches in length, three inches high, and three and a half inches broad ; all the sides arc straight, and at right angles to each other : the mouth is cut through the solid of the stock to receive the iron, and hold it at such an elevation, as to make an angle of forty-five degrees with the face of the plane ; the iron is a thin metal plate, one side consisting of iron, the other of steel ; the lower end of the iron is ground to an acute angle off the iron side, forming a sloping part called the basil of the iron, so as to bring the steel side to a sharp edge : the wedge which fixes the iron in its ',lace is let into two grooves of the same form, on the sides of the opening or mouth : two sides of the wedge are parallel, and it is forked, or cut away in the middle, leaving the sides like two prongs, to fill the lower part of these grooves; this allows the shaving to pass up, without obstruc tion, before the wedge : for the mouth or opening through the stock must be uninterrupted from the thee to the top, and must be no wider on the thee of the plane. than is suffi cient for the thickest shaving to pass with ease ; and as the shaving is discharged at the upper side of the plane, the opening through it must expand or increase from the thee to the top, so as to prevent the shavings from sticking therein. A handle, called the tote, is fixed to the upper side of the stock, immediately behind the iron ; it is formed to the shape of the hand, and the direction of the 'notion, so as to produce the most power in pushing the plane forward.
A workman in using the jack-planc, lay s the piece of wood on the bench parallel to its sides, with the thrther end lodged against time bench-hook ; then laying the flire part of the plane upon the hind end of the wood, with the right hand he takes the handle, and pressing with his left upon the fore-end, thrusts the plane forward in the direction of the fibre of the wood and length of the plane, until lie has extended the stroke the whole length of his arm, the shaving being discharged at the orifice; he then draws back the plane, and repeats the operation in the next adjacent rough part, proceeding in this Manner mail he has removed the rough parts throughout the whole breadth. lie then steps forward the distance of the length he has planed, and operates upon another length in the same manlier, proceeding this way by steps until the whole length is gone over and rough-planed. To do this is very easy ; but a workman will not make good progress, nor do clean work, unless he has first adjusted his tool properly for the work. The methods for doing this are nearly the same
for all planes. The first care is to obtain a sharp cutting-edge to the iron ; if it requires grinding on the grindstone, the carpenter places his two thumbs under the iron. and the fin gers of both hands above, laying the basil side to the grind stone, and holding it to the angle he intends it shall make with the steel side of it, keeping it steady while the stone revolves ; and pressing the iron to the stone with Ids fingers; in order to prevent the stone from wearing the edge of the iron into irregularities, he moves it alternately from edge to edge of the stone, with so much pressure on the different parts, as will reduce it to the required bevel, and make the edge straight.
The basil being brought to a proper angle, and the edge to a regular and slight curvature, the rouLdiness occasioned by the gritty particles of the stone is taken away by rubbing its edge on a smooth flat stone, or turkey-stone, sprinkled With olive-oil on its surface. As the basil is generally ground, to give a more acute angle than the edge of the iron would stand, for the quicker dispatch of wetting it. the face of the iron is inclined nearer to the perpendicular, while it is rubbed backwards and forwards with the same inclination throughout. Every time the iron becomes dull or blunt by use, the sharpening is produced by grinding on the rubber stone, or flat grindstone, or on a turkey-stone ; but, in repeat this, after the edge gets thick, it requires so much time to bring it up to an edge, that recourse must be had to the grindstone. The iron being thus sharpened, must be fixed in the plane by its wedge : the projection of the cutting edge must be just so much beyond the thee of the plane, as that the workman may be able to work it freely in the act of planing, and must be regulated by the stuff to be wrought, whether it be hard or soft, cross.grained or aiding; so that a man may be able to perform the most work, or reduce the substance most in a given time. It' the stuff is good and clean-grained, it is evident that a considerable projection may be allowed, as a thicker shaving may be taken. The extreme ends of the edge of the iron must never enter the wood, as this not only retards the progress of working, hot chokes mid prevents the regular discharge of the shavings at the orifice of the plane. -The projection of the cutting-edge is called iron, and the plane is said to have more or less iron, as the projection is greater or less ; when there is too much iron, the workman knocks with a hammer on the lore end of the top of the stock, and the blows will loosen the wedge. and raise the iron in a certain degree, after which the head of the wedge must be knocked down to fix it again. 'When the work man has occasion to take out the iron to sharpen it, he strikes the fore end of the top of the stock smartly with the hammer, which loosens both the wedge and the iron.