Sand-Papering (). The use of sand-paper should be confined to the removal of the minute fiber which is raised and left by the plane. This fiber is usually invisible, but its presence may be detected by comparing a surface newly-planed with a similar surface upon which sand-paper has been judiciously used; the latter will be much smoother. In applying sand-paper, the motion should be "with the grain." To prevent the destruction of sharp corners or delicate features of any sort, the sand-paper should be held about, or fastened to, a block of wood corresponding somewhat to the form of the work - a flat block for a flat surface, a curved block for a curved surface. A piece of thick leather is sometimes used instead of the wooden block, and is often more convenient, as it may be bent to fit almost any surface.

Sand-paper will not satisfactorily reduce irregularities in a surface, and should never be substituted for the scraper. As has been implied, it will simply remove the fiber, and a few strokes arc generally found to be sufficient; more are likely to result in injury.

Fig. 164

Exercise No. 5. - Box.

The stock required is 7/8" X 6" x 24 1/2"; it must be lined as shown by Fig. 165, and cut into five pieces. The finished box is shown by Fig. 166.

Fig. 165

147. If on each of the five pieces there is a surface sufficiently true for a working-face, it should be marked as such; otherwise, a working-face should be made. From the working-face joint one edge on each piece and mark it as the working-edge. Set the gauge at 2 3/4" (the inside depth of the box) and gauge the side and end pieces to this depth, after which joint them to line. From the working edge, with the try-square, scribe on the working-face of all the pieces, including the bottom, a line about 1/4" from one end. With the back-saw (56) cut these ends, being careful to keep on the outside of the line (148). The work may be held on the bench-hook, as shown by Fig. 167.

Fig. 166

Elevation.

In starting the cut, the saw may be made to act across the angle of the work in the direction of the line ab, but should gradually be brought to the position shown, its motion being parallel to the face of the work, and its stroke long enough to bring every tooth into action. The position of the saw in Fig. 167, together with the dotted outline, shows a proper range of movement.

Fig. 167

The ends, when sawed, should be square with the working-face and working-edge. If the cut is a poor one, a second may be taken by removing just enough material to hold the saw; if it is only a little "out," it will be best, in this case, to pass the error for a time. One end of each having been squared, the pieces may now be brought to length. On one of the two pieces which are to form the ends of the box, lay off and scribe a line 4" from the squared end. Measure the second end piece by the first to insure the same length for both, whether the measurement is just 4" or not. Next, on one of the two side pieces, 9 1/2" from the squared end, scribe a line for sawing and, using the first piece as a measure, lay off a similar line on the second side piece and also on the bottom piece. All the pieces having been thus lined, they may be cut with the back-saw, after which all but the bottom piece will be of the dimensions required.

148. Sawing "outside of the line" may be illustrated as follows: if two lines are made on a piece of work just 12" apart, and the portion between cut out by sawing exactly on the lines, it is obvious that the piece will be less than 12" long by half the width of the saw kerf at each end, or, adding the two deficiencies, by the width of one kerf, 1/16" or more. The appearance of an end when cut outside of a line will be that shown by Fig. 168. The smooth line along the upper surface, represents the cut made by the scriber in lining the material; the rest shows the work of the saw.