A sewing machine uses two threads to sew a seam. One unwinds from a reel, lies on top of the fabric and is pushed through the fabric by the needle. On the underside, it loops through the second thread, which unwinds from a bobbin in the shuttle and runs under the fabric.
The tension draws the threads taut, so that the loop is centered between the layers of fabric, and the stitches on top and underneath are identical. All the machines can be identical in appearance. The distinguish information in the models are provided at sewing machine buffs website for the benefit of the tailors. The layers of the fabric will be stitched from top to bottom or vice versa as per the requirements.
Choosing thread, needle and foot
Choose the thread and needle to suit the fabric. Use a cotton or silk thread for natural fibers such as cotton and linen; use silk or synthetic threads with woolens and a synthetic thread for man made fibers. One thickness of polyester thread suits most synthetics.
Cotton thread is made in a range of thicknesses – the higher the number on it, the finer the thread; 60-100 is for lightweight, 30-40 for heavy fabrics such as corduroy and toweling, and 20 for canvas. For upholstery fabric, use a strong thread such as flax, polyester, or heavy-duty cotton, or cotton wrapped polyester.
Use a sharp pointed needle on woven fabrics, a rounded tip on knitted fabrics and a wedge tip for vinyl or leather. Your machine manual will tell you which size to select. Generally, the sizes are : 70 metric for fine fabrics such as silk; 80 for normal use; 100 for heavy fabrics; and 110 for very thick fabrics. Round tips are 70 (lightweight), 80 (medium), and 100 (heavy); wedge tips are 70 (soft leather), 80 (medium) and 100 (very thick). Fit the needle as the manual indicates.
Fit the correct presser foot for the seam you are sewing. The foot fitted as standard is for straight seams – and sometimes zigzag seams. The range of alternative feet varies with the price of the machine; it may include feet for zippers, buttonholes, embroidery, over-sewing, invisible hemming, darning, narrow hems, stretch stitches and twin needles.
Threading and adjusting
Fill the bobbin for the shuttle with thread – most machines now have an automatic winder which disengages the needle while the bobbin is filled. Fit the bobbin in the shuttle with a tail of thread coming off clockwise as you hold the shuttle bobbin side up. Push the shuttle in place and pull the tail of the thread up to the work surface of the machine.
The sequence for threading the machine is generally the same. Take the thread from the reel round the tension control device, through the take-up lever and then down to the needle; there are thread guides to ensure the thread is not pulled off course.
Raise the needle by turning the fly wheel. Make sure you thread the needle in the direction shown in the manual; some machines have a built-in needle threaded. Raise the lower thread.
Plus in an electric machine and place the pedal conveniently. Adjust the controls to produce the stitch you want. A dial controls the stitch length; usually the thinner the fabric the shorter the stitch. The machine manual will have a chart to show the setting for any fabric.
Set the stitch width control; this may be zero for a straight seam, or a swing to right or left for a buttonhole, or an even swing for zigzagging. Higher numbers give wider stitches. Some machines will set length and width automatically when you touch a panel to select the stitch pattern.
Adjust the thread tension control dial as the manual recommends for the fabric, then do a test seam on scrap fabric. If the two threads are engaging on top of the fabric, release the tension by turning the control to a lower number; if they are engaging below the fabric increase the tension.
The dial alters the tension of the top thread; there is a screw on the shuttle to alter the tension of the lower thread but this is rarely necessary.
With the presser foot, take-up lever and needle raised, put the fabric under the foot with the seam edge to the right and the main volume of fabric to the left. Turn the fly wheel to insert the needle tip into the fabric at exactly the right point. Lower the presser foot to grip the fabric. Press the pedal to start the machine.
Most electric machines have a button which you can press to reverse the directions of sewing. This js useful for securing the seam ends. When you are starting a seam, insert the needle a short way in from the beginning of the seam, and sew in reverse to the edge before releasing the button and sewing forwards.
At the end of the seam, sew in reverse for a short way. Raise the foot and needle and pull the work backwards to draw out a length of thread before cutting off both threads. Pull the top thread to the underside, and cut of both threads with the built in blade or with scissors. If your machine does not sew in reverse, pull the top thread the underside and tie the threads together to secure them before cutting them off.
Do not push or pull the fabric through the machine. Simply prevent it from wandering to left or right. Use the edge of the presser foot as your visual guide as you sew.
At a corner, stop with the needle in the fabric but on its way up. Raise the presser foot and swivel round to the required position. Lower the presser foot and start sewing again. To sew a curve, go along slowly, turning the fabric gradually as you sew. If the curve is sharp or the edge begins to buckle, stop with the needle in the fabric, raise the foot, reposition the fabric and then lower the foot and continue sewing; you may need to do this several times round the curve.
After using the machine, clean and oil it with the fine brush and oil dispenser supplied. Have the machine serviced by the dealer regularly.
When the machine is out but not in use, put on its carrying case to keep out dust, and unplug it.