Paragraph 23. It is sometimes necessary to join two pieces of material with a straight butt joint where toe-nailing would not be satisfactory, or, at least, inconvenient. For this purpose the corrugated nail has been devised. A corrugated nail is simply a wavy piece of sheet steel sharpened at one end. These nails vary in length and width. Figure 39 shows an illustration of these nails and how they are used. The two pieces of material are brought together in a perfectly fitting butt joint, then the nail is driven across the joint standing practically at right angles to the line of the joint.

The illustration shows a mitered joint fastened with two corrugated nails, one entirely driven and the other in the process of driving; it also shows the square joint being made in a similar way. By driving two or three corrugated nails into such a joint a very strong piece of work can be made. Sometimes two nails are driven from one side, the work is then turned over and two or three are driven from the other side; this is done only where great strength is required. You will notice that the corrugated nails show even when they are entirely driven; for this reason they are not used in fine work, unless the joint is of such a nature that the nail can be driven from the wrong side. They are used considerably in the making of window screens and in various lines of cheap construction which do not demand a cabinet finish. The great advantage of the corrugated nail is strength and speed in construction.

Figure 39.

Figure 39.