This is a tool shaped as shown in Fig. 6, and is the one used first on a rough piece of wood, or when it may be necessary to reduce the size considerably. Either this planing down or the removal of roughness might be done with another and finer plane, but then there would be more labour and risk of injuring the finer tool and unfitting it for its special work. The jack plane, then, is the one with which rough planing is done, and is used both to save time and the other planes which come after it. The usual length is about seventeen inches, and the width of the iron two and a quarter inches. The back iron, as only coarse, rough shavings are required to be taken off, should be set back about one-eighth of an inch. I may here venture on a piece of personal experience, from which those who can read between the lines may derive a useful lesson. An amateur complained that his jack would not work easily, and that nothing more could be done with it than with the trying plane. The explanation was not far to seek, for it was found that the edges of the back and cutting irons were close to each other. He knew this was right for a smoothing plane, and concluded it must be so for the other, forgetting that the two tools are for different kinds of work. To be scientifically correct, the angles at which the irons should be ground and placed in the stocks would vary, but in practical work this is very little regarded; in fact, I may say not at all in the workshop. The ordinary common pitch of the iron does very well for all the purposes of the cabinet-maker, and as for the angle at which the tool is ground, no special care is taken to get it scientifically correct. A good wide bevel is what is best, and a suitable one is shown in Fig. 7. The difference between it and that shown in Fig. 8 will easily be recognised. The bevel, it must be observed, is on the hinder or lower surface of the iron, the back iron having its edge in the opposite direction, so that when placed together they are as in Fig. 9. The grinding does not put a cutting edge on tools, for this must be done with the oil-stone, and is only referred to here to say that after a plane iron or any cutting tool has been repeatedly sharpened, the edge gets as shown in Fig. 10, and requires regrinding occasionally.
Fig. 6. - Jack Plane.
Fig. 7. - Angle for Plane Iron Edge.
Fig. 8 .- Unsuitable Edge.
Fig. 9. - Plane Iron.
Now a plane iron must be carefully ground, so that the edge is on a line with the sole. If it is on the slant, one side of the iron will project more than the other, with a corresponding difference in the thickness of the shaving removed. The iron will dig into the wood at one corner, and perhaps not act at all at the other. The work in such a case is bound to be defective. Though the sole of a jack plane may be flat, it is better to give the iron a very slight curve than to have it straight. Absolute smoothness is not got with this plane, and the slight convexity given to the blade facilitates the work. The curve, however, should be of the slightest, so that the whole width of the iron may act. If it is too great the iron will project so much towards the centre that it might be impossible to plane, unless the corners are within the mouth and consequently inoperative, in which case a cutting iron of, say, two inches, would not accomplish more than one of considerably less. To prevent the novice rounding the iron too much, perhaps it will be as well to suggest that the aim should rather be to get the corners slightly rounded off, as in Fig. II, and only a very slight curve from corner to corner. Sharp corners and a straight edge do not answer in a jack plane. The irons are kept in position in the block by a wedge. This should be knocked in sufficiently firmly to hold the irons, which are kept together by a screw, firmly in their place. To loosen the wedge and remove the irons the plane is struck on top in front of the opening.
Fig. 10. - Edge requiring regrinding.
The Trying Plane in general shape is similar to the jack; indeed, one may be used for the other, if kept specially for the work, and is shown in Fig. 12, where it will be seen that the principal apparent difference is in the shape of the handle. The length of the stock is, however, greater than the other, 22 inches being generally recognised as suitable. The edge of the iron should be straight across and the corners square, or only just so slightly rounded as to prevent them catching in the wood. This plane is used to level the inequalities left by the jack and to get the surface true. The back iron should be set closer to the edge, as large shavings are not wanted. Very closely akin to the trying plane is the jointer, which only differs from it in length. This is usually from 24 to 30 inches. Though it may be a useful tool occasionally for long, straight edges, it is by no means indispensable to the cabinet-maker, many of whom never use one.
Fig. 11. - Curve of Jack Plane Iron.
The Smoothing Plane is used whenever a very fine, smooth surface is wanted. It is a much smaller tool than the others, and is of a somewhat different shape, as shown in Fig. 13. As the smoothing plane is only used for fine work, it should be kept exclusively for this and not be used on coarse rough wood. The blade should be ground straight across like that of the trying plane, and the edges of the two irons be very close together. To remove the wedge this plane is knocked on the back a little above midway between top and bottom. A smoothing plane with a wide mouth is comparatively useless. Either an entire iron sole or merely a front can be added to a wooden plane at any time, being supplied by many dealers. The novice is not advised to fasten them on himself. Rabbet or Rebate Planes, as shown in Fig. 14, are used for cutting away the edges of wood and forming a rectangular hollow. This work might be done with a chisel, but the difficulty of getting the depth and width regular would be much greater than with the special plane, which is neither more nor less than a block of wood holding a specially adapted chisel-like blade in one position. The iron, which is single, is at the lower end of the whole width of the sole. The block is of equal thickness throughout, and it will be noticed that the shavings as they are formed escape by an opening cut through from side to side instead of on top. The width of the iron varies, but one inch is a good, useful size. The mouth is either square across or skew, and it does not much matter which, though as the latter is better if anything than the other on hard wood and cuts soft equally well, it is, perhaps, preferable. The corners of the iron should not be rounded.
Fig. 12 - Trying Plane.
Fig. 13. - Smoothing Plane.
Fig. 14. - Rabbet Plane.
The Ploughing Plane (Fig. 15), or, as it is generally called, merely the Plough, is used for cutting grooves. As these are required of different widths, a set of eight irons is sold with each block, and are adaptable to it. By means of a screw on top the depth to which the irons will plough is regulated, as it is often of importance to get a number of grooves cut alike. To ensure the groove being straight, a movable fence forms part of the tool.
Toothing Planes in general appearance are similar to smoothing planes, but the iron instead of being at an angle is set vertically. The action of this tool is entirely a scraping one, and its principal use is to roughen surfaces when necessary to cause the glue to hold well to them, and to scrape down veneers on which a smoothing plane could not be used. The edge consequently is toothed very much like that of a saw, only instead of being filed they are formed by the front of the iron having a number of triangular grooves up and down its surface, so that on the blade being ground or sharpened these form a series of angular teeth on the edge. It is well to have two irons, one with coarse and the other with fine teeth, for different kinds of work.
The Old Woman's Tooth may be bought ready made - I hope no amateur will think I am taking 'a rise' out of him in suggesting this as a cabinet-maker's tool, for it is one in spite of its peculiar name - but there is no reason why the user should not make it for himself.
Essentially it is, or may be described, as a plough, but one of the crudest form, and little more than a block of wood with a hole through it in which a chisel or other cutting edge can be fastened by a wedge. It is used for cutting 'grooves or rabbets which could not well be managed with a plough or rabbet plane; as, for instance, when the groove or rabbet is stopped short and does not run from end to end of the wood. Its action is somewhat rough, but it speedily removes waste wood to a uniform depth, this being regulated by knocking the iron through the stock. There is no universally adopted size or pattern, as being so often a 'homemade 'tool the user forms it according to his own fancy. Fig. 16 shows as useful a shape as any. The edge of the iron should be as near the front of the block as convenient. The hole shown may be omitted.
Fig. 15 - Plough Plane.
Hollows and Rounds are planes something after the same style as a rabbet plane, but instead of having a flat sole they are either rounded or hollowed, and, of course, their irons are shaped to correspond. Their use is for working mouldings, and if only very plain furniture is to be made, or if, as is often the case now, mouldings are worked by power instead of by hand tools, they may almost be dispensed with. The young cabinet-maker working in a shop where steam or gas power is used will not have much need of them, though it is always an advantage to be able to form one's own mouldings. These planes are sold in pairs, of which sixteen form a full set, but a half set or eight pairs, made up of alternate sizes, will be sufficient for all ordinary requirements. In grinding and sharpening the irons great care must be taken to preserve the sweep, and not to alter it from that of the sole. To sharpen the hollows rounded slips of stone are required.