There are different ways of looping the upper thread around the lower thread. One way is shown in Fig. 6. As the needle takes the upper thread down it makes a loop as in the first picture of Fig. 6. The lower thread is in a shuttle which moves backward and forward. This shuttle moves forward, passing through the loop as shown in Picture 2 of Fig. 6. Picture 3 shows the needle pulling the upper thread up around the lower thread. When the threads are drawn tight it makes a stitch.
Another way of looping the upper thread around the lower thread is shown in Fig. 7. This type of bobbin rotates as shown by the arrows. A hook catches the upper thread and carries it down and around the bobbin so that it comes up on the other side of the lower thread. This makes the stitch when the threads are drawn tight.
Examine the machines in your classroom and at home to see if you can tell how the stitch is made. In some machines it is possible to see below the table and as the needle is moved up and down very slowly you can see the stitch being made How the Cloth Is Held in Place. - As you watched the machine stitching, you noticed that the cloth is held firmly and moves constantly, so that a continuous line of stitching is formed. The part of the machine which holds the cloth in place is called the presser foot and can be raised or lowered by means of a handle. Picture 1 of Fig. 8 shows the foot raised with the handle up. This picture also shows the part of the machine which causes the cloth to move. This part is called the feed and consists of small teeth which catch hold of the under side of the cloth and pull it along. These teeth move the cloth along just as your fingers do when you are sewing by hand. In Picture 2 of Fig. 8 a piece of cloth has been put in and the presser foot lowered to hold it in place. The feed is underneath the cloth, ready to move the cloth along when the stitching is begun.
What Makes the Machine "Go." - In order to make the stitch properly, the parts of the machine, the needle, the bobbin case or shuttle, and the feed must all move at the same time. A sewing machine is so wonderfully put together that all these complicated parts can be made to move by simply moving one part of the machine. If you will examine Fig. 9 you can see how all the parts of a sewing machine are connected. The orange color shows the parts which move. The picture shows the rods inside the top part of the machine which connect the needle bar with the wheel at the back and also the rods which connect the shuttle with this same wheel. This small wheel is connected with the large wheel below by means of a leather belt. Therefore, when one wheel moves the other also moves and since the rods are also connected with the small wheel they too move. The large wheel is connected with the treadle by a rod which is fastened to this wheel at a point just away from its center. The treadle moves up and down, causing the large wheel to revolve, which in turn revolves the small wheel. This causes the connecting rods to move, thus moving the needle, the shuttle, the feed and other parts.
After studying the picture see if you can follow the way these parts are connected in a real machine.
Care of the Sewing Machine. - You have learned that the sewing machine is a complicated piece of machinery. Any machine from which one expects to get good service must be well taken care of, and there are a few things you should do for the machine you use. This applies when you use a machine that is not your own as well as when it is your own personal property. Be sure to do your share in caring for the machines in your classroom.
1. The head of the machine should be let down or covered when not in use so that it will not get dusty.
2. Dust the machine with a soft cloth before using it.
3. Let the head down slowly so that it will not be jarred.
4. From time to time the machine should be oiled, in order to make it run easily and to save wear on the parts.
When a machine runs hard it may be that the machine needs oil.
Causes for Difficulty When You Are Stitching. - In your future work on the sewing machine you may have difficulty occasionally with the thread breaking, the needle breaking and the thread knotting. You should know the causes for these difficulties and be prepared to remedy them yourself. Instead of bothering your teacher, consult this page in your book and try to make the repair yourself.
If the upper thread breaks:
1. The machine may not be properly threaded.
2. The tension may be too tight.
3. The needle may not be set correctly.
4. The needle may be too fine for the thread. 5. The needle may be crooked.
If the lower thread breaks:
1. The shuttle may be incorrectly threaded.
2. The bobbin may be too loosely wound.
3. The bobbin may be too full.
4. The hole in the steel plate may be rough and cut the thread.
5. The lower tension may be too tight.
If stitches are skipped:
1. The needle may be blunt or crooked.
2. The needle may not be correctly set.
3. The thread may not be the right size for the needle.
If the needle breaks:
1. The material may have been pulled.
2. The presser foot may be loose and in the way of the needle.
3. The needle is too fine for the material.
If the material puckers:
1. The upper tension is too tight.
2. The stitch is too long for the material used. 3. The needle is blunt.
4. The hand holds the material and prevents it from feeding through as quickly as it should.
Are You a Good Citizen in Your Sewing Class. - Your sewing class is a small community in which each member has certain responsibilities. Discuss with your class what each girl should be expected to do to make the sewing room a good workshop. Decide what each girl can do to be a good citizen in your sewing class.
1. Who should close the sewing machines at the end of the class period?
2. Who should put away your scissors, thread and other sewing equipment?
3. Whose responsibility is the general order of the room?
The clearing of the tables? The placing of the chairs?
4. How much talking do you think there should be in a good workshop?
5. Do you ask for help from your teacher more often than is necessary? Do you take more of her time than is necessary?