There will now no doubt be two classes of boxes in the class, as the result of the last exercise. The first will be smaller or larger than they were intended to be, or they will be not quite square at the corners, or they will be "winding," that is, when set on a flat surface like that of the bench they will touch at three corners only. The second will be true to dimensions and shape, and will be "out of winding."

The test for "winding' is important, and may be made in several ways. We cannot always depend on the test by laying on the bench as already described, since the bench itself may be in winding, or the object may be too large to be tested in this way, or too small to show the defect. A second, and more common way of testing an object of moderate size, such as one of your boxes, is to hold it up before one eye, keeping the other closed, and look across one of the edges at the other edge. If the front edge exactly covers the hind edge, there is no winding; but if one end of the hind edge stands up above the front edge when the other end is exactly covered, the object is winding. When the object is very small it is sometimes hard to detect the fault in this way. In this case the error may be exaggerated and made perceptible by means of "winding sticks." These are two "straight edges" or strips of wood with straight and parallel edges. Suppose two such strips, say 2" x 1/2" - 24; to be laid across your box at opposite ends. If the winding be too small to be noticed when you look across the box itself, you may yet be able to detect it when it is exaggerated by these long sticks. In this way, even the winding in the edge of a board may be detected.

This and the other tests being applied, we will suppose your boxes divided into two classes, as already described. Those of the second class, being perfect, or nearly so, we might finish up, by furnishing them with bottoms of the same material, fastened, like the sides, with nails. These boxes, being all of the same size, might be piled up in a set or "nest," and used for the stowing of nails, screws, glue, and other materials used in the shop. Instead of doing this, however, we will take the boxes of both classes apart, and use the material in making another set of boxes of better finish than these, and requiring the use of other tools and more practiced hands.

Exercise 13. Test For Wind-Ing

To knock your box apart without splitting it, hold it by one of the long sides and strike the other long side, inside of the corner, with a hammer. Do not strike directly on the wood, in which case you will probably split it, and certainly bruise it, but on a strip laid in the corner to receive the blow. If there is not room to strike with the face of the hammer, strike with the side. Striking in one corner and the other alternately, you will probably separate the box at two corners, and so take off one of the long sides, after which, holding the short sides and repeating the operation with the same care as before, you will take off the other side. Drive out the nails by striking them on the points, and straighten them by striking them gently with the hammer on the convex side while holding them on a block of wood, - not on the bench, as you would thus mar the bench.

Exercise 14. Taking Apart Nailed Work

For the new box that we propose to make, we will reduce a little the thickness of our pieces of wood, and give them a finer surface than the mill-dressed surface that they received from the planing-machine. Your exercises with the hatchet and the knife have shown you the difficulty, if not the impossibility, of finishing a piece smooth with either of these tools. You will be ready, therefore, to appreciate the value of the plane.