Practice retracing the ends of the line of stitching for one-half inch so as to make a neat and strong finish. This retracing should be done at the beginning and at the finish of each line of stitching as shown in the diagram. The needle must be left down while the cloth is turned. The retracing should fall exactly on the line of stitching. Where should the needle be put down first to make the retracing at the beginning of the line of stitching?
Another way of finishing a line of stitching is to pull both threads to the same side of the cloth and tie them in a knot. After the knot has been tied the ends can be trimmed off about one-eighth inch long.
Inspection of Your Machine Stitching. - Criticize your own and your neighbor's stitching on these exercises for the following things. Remember when you criticize to mention the good as well as the poor things.
1. Is the stitching straight or wobbly?
2. Are the corners square?
3. Are the ends retraced properly?
4. Are the ends tied neatly?
Length of Stitch. - It is possible to change the length of stitches in machine sewing just as it is possible to take long or short stitches when sewing by hand. The length of stitch is changed by moving the stitch regulator which is located near the bobbin winder and balance wheel. Sometimes this regulator is a handle which slides back and forth and sometimes it is a screw which is turned. Long stitches are best suited to thick, heavy materials and short stitches to thin materials.
1. Experiment with changing the length of stitch. Try to get a sample of stitching with a very long stitch and another with a very short stitch.
2. Try to do a sample of stitching with the best length of stitch for material such as gingham or muslin.
Tension. - Tension is best explained by placing a thread on the table, pressing your finger on it and then pulling on the thread. Press your finger down hard on the thread and then pull. If you press lightly on the thread the tension is loose, if you press hard the tension is tight. As you remember, when threading the sewing machine the thread passes between two little steel plates, called the tension discs. These plates can be made to press together more tightly or loosely by turning the screw. If the tension is too tight the thread may break, or, if it is too loose the thread may run through too rapidly and cause the stitching to be knotted and looped.
There is a tension on the lower thread as well as the upper thread but this seldom needs adjusting. It is generally possible to regulate the tension properly by adjusting the upper tension only. The first line of stitching in Fig. 4 shows a stitch in which the tension is perfect, the upper and lower thread each being drawn to the center of the cloth. It looks exactly alike on both sides. The second part of the picture shows a stitch in which the upper tension was too tight, causing the thread to lie flat on top of the cloth. If the tension on the upper thread is too loose it may make a stitch in which the lower thread lies flat and is not drawn into the cloth. When the tension is very loose it may form loops on the underside of the cloth.
1. Examine the machine stitching on your clothing to see if the tension was properly adjusted.
2. Examine a sample of the stitching from your machine to see if the tension is correct.
3. Where is the tension located on the machines in your classroom? On your machine at home?
The Sewing Machine Needle. - A sewing machine needle differs from an ordinary sewing needle in two ways. The eye is in the point of the needle and at the other end is a thickened part called the shank. One side of the shank is flat so that it will fit into the needle bar which holds it in place. The first picture of Fig. 5 shows an ordinary sewing needle as compared with a sewing machine needle. In Picture 2 of Fig. 5 the sewing machine needle is ready to be slipped up into the needle bar. The flat side is always toward the screw on the needle bar. If the needle is not put in properly it may break or cause the thread to break.
How the Stitch Is Made. - The needle moves up and down through the little hole in the table, carrying the thread down and pulling it up again each time. Picture 3 in Fig. 5 shows the needle ready to carry the thread down through the hole. To push an ordinary needle up and down through a piece of cloth would accomplish nothing. How is it that the machine makes a stitch? After all, the thing that happens below the table is not so mysterious. As you know, there are two threads used in the sewing machine, one below and one above the table. When the needle carries the upper thread down through the little hole it is looped around the lower thread, locking them together to make the stitch.