Since the heads of brass screws are likely to break off under strong ton it is common practice to drive an iron screw in first, replacing it with a brass after the threads are cut in the wood. For careful craftsmanship, the screwdriv edge should be kept squared, so that it will sink into full contact with the grc of the screwhead. The edge should also be thick enough to fill the groove, in 01 to prevent it from slipping out under pressure and gouging the work. The wi of the screwdriver's edge should not exceed that of the screwhead, or the w will be bruised when the head is driven home. It is a sign of good workmans when exposed screwheads are driven hom3 so that all slots face in the same dii tion. The various sizes of nails are discussed in Chapter 9. wood joinery After this brief survey of elementary woodworking operations, the ambiti craftsman may be assumed to have graduated from the Junior College of Carpen and be considered ready for matriculation in the University of Wood Joinc It is well for him to reverence those ancient halls where once such masters Thomas Chippendale, the Adam brothers, George Hepplewhite, Thomas Sherat Duncan Phyfe, and others instructed eager contemporaries in an art wh L 3utt Joint в 24 . products were no stronger than their weakest joints. Lest the hesitant neophyte be overcome by the implications of these famous traditions, however, let him be reassured by the fact that, although good joints are indeed the product of careful, unhurried workmanship, they are not necessarily the product of skill. The careful planning of a logical procedure-a visualization of the various steps in their proper sequence-and the execution of the plan will insure success for the amateur as well as the expert craftsman. Lap joints. After the plain butt joint (Figure 1.24), which has two squared surfaces butted together and fastened with glue, dowels, screws, or nails, and the sloping scarf joint (Figure 1.24), which is at best but a compromise, comes, in order of simplicity, the lap or halved joint (Figure 1.25). This joint is easy to Z.ip ifoint Fig. 1.25. Lap joints. saw, for as its name implies, it is made by cutting out equal halves from both members so that when united, the joint is flush. When the halved joint is cut from the ends of two members meeting a right angles, it is known as an "endlap joint." If the members cross each other at right angles near their centers, the joint is termed a "crosslap joint'; if the end of one member joins the other near the middle, it is called a "middlelap joint." In marking lap joints, the best method is to lay one member on top of the other and scribe the exact position where the joint is to be cut; the depth is then marked on the sides with the marking gage. Endlap joints can be cut out entirely CABINETMAKING with the back or tenon saw, the vertical cuts being made first; with the cross or middle lap, the waste must be removed with the chisel.