This section is from the book "Clothing For Women: Selection, Design, Construction", by Laura I. Baldt. Also available from Amazon: Clothing For Women: Selection, Design, Construction.
Can you imagine an engineer who is so unfamiliar with the parts of his engine, and their relation to each other, that his ear will not detect at once the slightest break in the rhythm of the motion, bespeaking something amiss, and telling him just where the difficulty lies? Just as familiar should you be with your sewing machine. You should know equally well how to use and care for it, and understand its parts in relation to each other, so that minor difficulties can be adjusted by yourself without loss of time or expenditure of money. It is hoped that the brief survey which follows may help you to understand better how to handle your machine.
Cloth and Brush for cleaning machine
Small pair pincers
Strap-cutter and punch
Machines are of two types, single-thread with automatic tension, and double-thread or lockstitch, with adjustable tension. An explanation of these terms follows.
Spindle or Spool Pin, on which the spool of thread is placed.
Automatic tension (on single-thread machine), which controls the amount of thread pulled from the spool.
Pull-off, which pulls thread from spool.
Take-up, which pulls thread up from needle as each stitch is completed, and tightens the stitch in material.
Needle-bar, to lower end of which the needle is attached.
Presser-foot, which presses down on the material to be sewed, holding it firmly against the feed.
Presser-foot bar, to lower end of which the presser-foot is attached.
Presser-foot lifter, small handle by which presser-foot bar is raised and lowered.
The metal bars with roughened surfaces, which move forward, upward, backward and downward through an open space in the Cloth Plate immediately beneath the presser-foot, and pull the cloth toward the needle for each stitch. The distance which the Feed moves backward, pulling the cloth with it, determines the length of the stitch and is regulated by the "Stitch Regulator" in double-thread machines (a thumb-screw on the arm at the right). On single-thread machines there is a small slot in the front of the cloth-plate, through which numbers can be seen. These are moved by a handle under the Cloth Plate. The numbers range from twelve to thirty stitches to one inch, and are changed to suit the size of the thread used and the material to be sewed.
Cloth plate, the metal plate over which the material passes while being stitched.
Bobbin, the metal spindle on which the under thread of a double' thread machine is wound.
Bobbin case or shuttle, which encloses the bobbin, and by rotating, vibrating or oscillating motion, interlocks the under and upper thread to form the stitch.