In m; such a box care should be exercised not only that the front and back are sc with the base, but also that their tops are level, so that when the steel fra square is laid on their edges it too will be level. For 450 kerfs equivalent marks on both legs of the square are lined up on the same side of each edge, Figure 1.6. For accommodating wider pieces, some mechanics prefer the t Fig. 1.6. Laying off 45° angle in miter box. Fig. 17. Bench hook. book pictured in Figure 1.7. Because all saw cuts are made on the forward sti tte bench hook is automatically held in place without clamps bv the pres against the lower strip or hook. However, since there is no rear member to g marking is necessary. 12 . For sawing miters in very wide material the method shown in Figure 1.8 will prove successful. A jig is made made by cutting two 45° kerfs in a piece of 2in. stock (or iin. hardwood), 10 or more inches in width. The material to be mitered is held firmly in the bench clamp, and a Fig. 1.8. Miter jig for deep cuts. straightedge piece is adjusted loosely in clamps until it is in the proper position as a stop for the jig at the desired cut. The straightedge is then trued up with a square and clamped in place with the jig clamped firmly against it. When the saw nears the bottom of the cut the jig is lowered against the straightedge and reclamped. If a miter box is lacking, or if a board is too wide for the box, an accurate miter can be laid out with the try square. A line is first drawn along the edge of the square across the width of the board. From the intersection of this line with the board's edge the width of the board is laid off along the edge, and a line drawn across the board parallel to the first line. A diagonal between the proper corners of this perfect square will accurately place the miter. Saw Kerf Bends. To insure uniform bends in wood without steaming, a series of saw kerfs on the inside of the bend must be equally spaced so that they will all be closed at the top when the desired curve is achieved. In %in. stock an initial kerf % in. deep is cut and from it a distance is marked off equal to the radius of the required bend. With the far end of the lumber clamped to the bench top as shown in Figure 1.9, the opposite end is bent upward until the saw kerf closes. The Fig. 1.9. Calculating saw kerf bend. height measured between the lower edge of the board and the top of the bench at the radius mark will be the amount each kerf is to be spaced. All kerfs should be sawed to an equal depth. Planing. Many pieces of wood, after they are sawed to proper Imgth or CABINETMAKING ripped to the required width, need only be planed smooth to be ready for fasti in their proper places. Although it is a basically simple operation, planing, has a technique of its own. While it is true that the angle of the chisel or с is a deciding factor in the plane's manner of performance, various planes are structed for various operations.