Chapter 4 - The Sewing Machine

Operating a sewing machine is comparatively simple. Anyone can learn to do it well and proficiency is merely a matter of practice. You will get the most satisfaction and pleasure out of sewing if you own your machine and learn to use it well. Machines may be operated either by electric motor or by foot treadle. Practice first on paper and then on cloth. See p. 35 for practice suggestions if you are a beginner.

The upper part of the machine is called the head, and the large wheel on the right is the balance wheel. This is connected to the drive wheel, underneath the table, by a belt, and the two wheels turn together. The balance wheel is turned towards you to make the needle go up and down.

The presser foot (3) holds the material in place as you sew, and is lifted and lowered by means of the foot lifting level (6). The needle, which falls between the toes of the presser foot, is inserted into the needle bar (5) and tightened in place with a small screw. The needle must be inserted properly, straight up into the needle bar, with grooved side to right or left, depending on your machine.

Notice the other parts on the picture. The machine is usually threaded in this order: spool pin (1), thread guide (2), tension disks (3, 4, 5) and spring (6), take-up lever (8) at highest point, thread guides (7, 9), needle (10). The needle is always threaded from the side on which the last thread guide is, along the groove into the hole. Check your manual for exact details for your machine.

Use the same kind and size thread on the bobbin as on top of the machine, except for special effects. To wind the bobbin, wind some thread around it by hand until there is enough tightness so thread does not slip off, insert bobbin into bobbin winder, put thread on spool pin. Loosen the large screw in the center of the balance wheel so that needle no longer goes up and down, push winder into place back against wheel, run machine slowly to wind bobbin evenly, not so full that it fits into shuttle tightly. Tighten screw in balance wheel when finished.

In old type treadles, there is often a long bobbin and a shuttle into which it is inserted. Put the bobbin into the shuttle, holding the top in place with one finger of left hand. With right hand, pull thread down through slit to bottom where it catches in a spring and up again into center. Put shuttle into shuttle case, point first, flat side up. Pull up bobbin thread by holding upper thread in left hand. Turn balance wheel towards you slowly until needle goes down and up, catching bobbin thread in a loop. Pull up loop, and put both threads back through toes of presser foot. Close slide over shuttle case.

New treadle and electric machines have round bobbins which are wound in a manner similar to that described. See that small piece of metal on winder fits into hole on side of bobbin.

If the machine has no automatic bobbin winder release, be careful not to wind the bobbin too full or too tight or the thread may break in stitching. It is a good practice not to wind on a bobbin partly filled with thread. You may be deceived later about the amount in the top winding and forget what kind of thread is underneath. If you lack bobbins and must wind on top of another thread, be sure the thread ends underneath are caught under the new thread and not left loose to tangle and cause the new thread to break.
 
Learn to treadle smoothly with both feet flat on treadle, left foot in upper left corner, right foot in lower right corner. Turn balance wheel with hand and the treadle will begin to move. You must continue the movement with an even pressure of the feet to get a uniform, back and forth, motion. Stop by putting hand on the balance wheel. Learning to treadle without jerking the wheel back is most important and fundamental. Practice treading before you thread the needle until you can always get the balance wheel to go in proper direction—in most machines, towards you. If the wheel goes the wrong way, the thread will break and you will have to rethread your needle and start your line of stitching again. Practice on paper first and then on cloth. Use the following types of designs to practice on the machine: straight lines, circles, mazes, wavy or scalloped lines, crossed loops as in flower petals, and any other design that appeals to you. Work on double thickness of paper.

Be sure to remove the belt from the wheel when opening or closing the machine, if your machine requires this. Put belt in proper position again before starting to stitch. If belt breaks or is too loose, open the metal hook with pliers. Cut off a piece of the belt, punch a hole in one end and clamp the hook back. The sewing machine company will sell you an instrument which has pliers, special cutter and hole punch combined.

On electric machines, the secret is to get the machine operating at the speed you want. You must practice pressing the foot button or knee lever till you can make the machine crawl at an even tempo. If you can work it slowly, you can work it fast. The upper thread is threaded in a way similar to that described above. For bobbin thread, place bobbin in case, holding thread forward or back according to machine, catch the thread in slot and then pull it in the opposite direction to catch in notch. Reversing the direction of the thread gives proper amount of resistance. The bobbin may have detachable bobbin case latch into which bobbin fits. Bobbin is inserted into bobbin case and thread pulled up as above.

Always be sure the machine is wiped clean before you start to stitch.

At all times, start to stitch with a practice piece of fabric to be used for garment. Select proper size needle and thread (see table, p. 5.) Never allow a stitch to be taken without cloth under the needle. Watch beginning and end of stitching lines for this. Stitch a short line and check size of stitch and tension. Stitch regulator at right will change size of stitch by your moving the lever up and down or turning dial. In most machines, the higher the number, the smaller the stitch. Twelve stitches per inch is usual regulation but shorter stitches are used for finer fabric and longer stitches for heavier cloth and for plastics and nylon. If stitch length isn't specified on the stitch control, stitch a short distance, measure off an inch and count the number of stitches in the measured inch.

Tension is correct when both sides of the stitch look the same. This is because upper and under threads loop in center of material. If loops appear on the top, the upper tension is too tight and is pulling the under thread, or the bobbin tension is too loose. If loops appear on underside, the reverse is true. Bottom tension is regulated by a tiny screw and is best done by someone with experience. In general, plan to adjust upper tension only, by turning screw or numbered dial to right to make tension tighter, to left to loosen. If tension is too tight, the thread will break. Always have presser foot down when you loosen or tighten tension.

When starting to stitch, see that take-up is at highest point, and both threads are back through toes of presser foot. Hold these threads loosely for the first few stitches to prevent bunching of the thread. Put down needle and presser foot, guide material with light pressure of hand. Do not pull or hold material taut; the feed dog will keep the material moving. Pushing or pulling the material will produce imperfect stitches and may cause the needle to bend or break. See that material does not hang unsupported from sewing machine table. In general it is best to stitch with the seam at the right-hand side of the goods. This is more convenient for the right-handed worker and keeps the material from being crushed and wrinkled in the limited space under the head. For this reason the seam

guide is attached to the plate at the right of the feed dog.

To remove work from the machine, stop machine by putting hand on balance wheel, bring take-up lever to its highest point, raise presser foot, pull work back, not forward, and cut threads on machine cutter behind presser foot, or with scissors. Leave enough thread from needle and bobbin so that you can start to stitch again without having needle become unthreaded.

A machine kept clean, oiled, and correctly adjusted should produce perfect stitching. If there is any difficulty in securing good results, consult the summary of machine troubles and their possible causes below, and make the adjustments indicated.

These are some common machine troubles and their causes:

1. Tangled thread at beginning:

bobbin too full or bobbin thread wound in wrong direction.
under thread not drawn up or both threads not pulled back under presser foot.
 
improper oiling or cleaning of machine.

2. Jammed machine: threads jam bobbin case.

3. Machine runs hard: lack of oil; thread wound around wheel and treadle bearings; gummed oil or dirt in bearings; tight bearings; belt too tight; bobbin winder against wheel or belt during stitching.

4. Imperfect stitches (looped stitches on top of cloth or upper thread lies straight along top of cloth): upper tension too tight or lower too loose; bobbin incorrectly threaded; dirt, lint, or rust between upper tension disks; dirt, lint, or pieces of thread under lower tension spring.

5. Looped stitches on lower side of cloth or lower thread lies straight along bottom of cloth: incorrect threading, upper tension too loose or lower too tight; dirt, lint, or rust between upper tension disks; dirt, lint, or pieces of thread under lower tension spring; dirt, or lint in end of shuttle or bottom of bobbin case; shuttle too tight in shuttle carrier.

6. Skipped stitches: needle bent; needle too small for thread; needle set too high or too low; needle set wrong side out; needle incorrectly threaded; needle too long or too short; oil on needle or too much on shuttle race; shuttle point blunt or worn.

7. Staggered stitches: too little pressure on presser foot; take-up spring weak, broken, or missing; incorrect adjustment of take-up spring.

8. Stitches of uneven length: improper pressure on presser foot; feed dog not adjusted properly; dirt around feed works.

9. Upper thread breaking: poor, knotty, or rotten thread; machine threaded incorrectly; needle set wrong side out; needle set too high or too low; needle bent; needle too fine for thread; needle threaded incorrectly; needle rubs against presser foot, needle plate, or shuttle; rough or sharp places on shuttle or eye of needle; upper tension much too tight; in long-shuttle machine, not enough clearance between shuttle and shuttle cradle.

10. Lower thread breaking: poor, knotty, or rotten thread; lower tension much too tight; bobbin case or shuttle threaded incorrectly; burr or sharp edges on needle plate; bobbin wound too loosely or too tightly; bobbin wound too full; bobbin wound unevenly; rough or sharp edges on bobbin shoulders; rough or sharp edges on lower tension spring; dirt or thread in shuttle cavity so bobbin cannot turn freely; packed lint in shuttle or bobbin case.

11. Material not feeding through machine correctly: stitch length regulator turned too far so feed is not acting; dirt under needle plate around feed dog; incorrect setting of feed dog; incorrect pressure on presser foot; bent presser foot or feed dog.

12. Bobbin won't wind correctly: drive wheel on winder not bearing heavily enough on hand wheel or belt; rubber tire on bobbin-winder wheel loose, oily, or worn; thread guide on winder bent so thread piles up at one end of bobbin; cam wheel that operates thread guide not turning freely or incorrectly set.

13. Clutch not releasing hand wheel: hand wheel bearing gummed; clutch bound with thread or gummed with dirt, thread, or oil; incorrect assembling.

14. Hand wheel hard to turn or set: thread jammed in shuttle race; thread or dirt in bearings; bearings rusted or gummed; bearings too tight.

15. Runs noisily: lack of oil; loose bearings; shuttle loose in its carrier; loose bobbin case.

16. Puckers in cloth: seam puckers—one or both tensions too tight; side puckers—dull needle.

17. Needle breaking: pulling the material while stitching; needle too long or set too low; presser foot incorrectly attached; failure to raise needle before removing material.

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