Use of the Hand-sewn Hidden Stitch and the Needle Used

The hidden stitch is usually used to make repairs on upholstery and on clothing where good appearance is important. To make this stitch, select a 2 1/2-inch curved needle and a length of suitable thread. Thread the needle to sew with a single thread and tie a knot in the long end. Fold under one-half inch of material and place it on the other piece of material, as shown in figure 10-31. Start the stitch by pushing the needle through the back of the fold, about one-eighth

Figure 10-30.-Forming a lock knot for the baseball stitch.

inch from the end. Pull the needle through the bottom material at a point directly below where the needle came out of the fold. Guide the needle so that the point comes out again about onefourth inch along the line of the seam. The point should come out directly below the creased edge, as shown in view A of figure 10-31. Pull the needle and thread out to draw the stitch tight. Push the needle into the front edge of the fold directly above the point where the needle came out of the bottom material. Guide the needle point along the inside of the fold so that it again comes out the creased edge about one-fourth inch from where it entered, as shown in view B of figure 10-31. Pull the stitch tight and repeat the previous steps until the end is reached. Finish the seam off by coming back one stitch (through the opposite material) so that the needle reappears alongside the exposed thread of the next-to-the-last stitch. Tie two half hitches around the exposed thread.

MACHINE-SEWN SEAMS

Chances are you have been accomplishing sewing projects since you arrived at your new assignment. Then again, you may have done no sewing at all. The amount of sewing done in your shop depends upon the mission of your base. If your unit does much fabrication, then you probably will do quite a lot of machine sewing.

Figure 10-31.-Hidden stitch.

In this section, we discuss techniques concerning machine-sewn seams. While there is generally no option in choosing a hand-sewn seam, there are many options in choosing a machine seam.

Advantages and Characteristics of a Machine-Sewn Seam

Machine seams or stitchings have the following advantages over hand-sewn seams: (1) speed, (2) appearance, and (3) uniformity of tension. Their desirable characteristics are as follows:

STRENGTH. Strength of a seam of stitching depends on the type of thread, stitch type, number of stitches per inch, the construction and tightness of the seam, and the size and type of needle point used. The strength of the seam should equal that of the material it joins. Use only the material specified for the assembly in the applicable technical order.

ELASTICITY AND FLEXIBILITY. Elasticity and flexibility depend on the stretching qualities of the material used, the quality and tension of the thread, the length of the stitch, and type of seam or stitch used.

DURABILITY. Durability is determined by the wearing qualities of the material, the quality of the thread used, and proper tension to set stitches well into the material to reduce abrasions. Relationship between the elasticity of the seam and the elasticity of the material is very important in determining durability.

SECURITY. The security of a seam or stitching depends chiefly on the stitch type and its ability to resist unraveling. The stitch must be well set in the material to prevent snagging, which can cause thread breakage and unravel some types of stitches. Seam "run offs" weaken a seam. All seam ends should be backstitched or anchored (backstitched and overstitched) to prevent the seams from unraveling, as illustrated in figure 10-32.