Paragraph 139. The lapped seam is a very strong smooth seam which lies perfectly flat. Its strength is due to the fact that it is sewed with two rows of stitching. It is made on the right side of the garment. To make this seam, turn up the edge of one piece of the material about 1/8" and turn down about 1/8" on the edge of the piece to which it is to be joined. Lap the two seams 1/4" to 1/2", as desired, baste them together down the center. If they are fitted, it will be necessary to turn in the edges according to the line marked in fitting. Stitch on the right side, as in Figure 45, stitching close to the edge of the material placed on top. Stitch as near the edge of the other as you can from the right side, but be careful to keep the two rows of stitching parallel, even though the second row does not stitch the edge of the under lap as evenly as it does the upper one. This seam is used principally in finishing the seams of tailored garments.
Paragraph 140. The overcast seam consists of an ordinary seam with the raw edges overcast to prevent raveling. To make this seam baste (Par. 103) and sew two edges of the cloth in a seam, on the wrong side, the width desired.
Press open the raw edges and overcast each edge separately as in No. 1, Figure 46, or leave the two edges together and overcast both at the same time, as in No. 2. This seam is used on heavy linen, wool, and silk materials where it is desirable to have the seam show as little as possible.