The basic structure of sewing machine is the same whether it is hand-operated sewing, treadle sewing machine or electric sewing machine. The basic parts of sewing are listed below.
 

Figure 1. 4 ; sewing machine parts. Photo credits; blogspot.com.

1. Spool pin: It is fitted on top of the arm to hold the reel.

 

2. Thread guide: It holds the thread in position from the spool to the needle.

 

3. Tension disc: The two concave discs put together with the convex sides facing each other. The thread passes between the two. The tension of the thread is adjusted by a spring and nut which increases or decreases pressure

 

4. Take up lever: It is a lever fitted to the body of the arm. It’s up and down motion feeds the thread to the needle and tightens the loop formed by the shuttle.

 

5. Needle bar: This is a steel rod to hold the needle at one end with the help of a clamp. Its main function is to give motion to the needle.

 

6. Bobbin case: This moves into position to catch the top thread and form the stitch as the needle is lowered into the bobbin chamber.

 

7. Presser foot: It is fixed to the presser bar to hold the cloth firmly in position when lowered.

 

8. Presser foot lifter: A lever attached to the presser bar for raising and lowering the presser foot.

 

9. Stitch regulator: This controls the length of the stitch.

 

10. Bobbin winder: A simple mechanism used for winding thread on the bobbin.

 

11. Fly Wheel: When this is made to revolve, it works the mechanism of the motion

 

12. Clutch or Thumb Screw: This is in the center of the fly wheel and it engages and disengages the stitching mechanism.

 

13. Slide Plate: A rectangular plate, which facilitates the removal of the bobbin case without lifting the machine.

 

14. Needle Plate or Throat Plate: A semi-circular disc with a hole to allow the needle to pass through it.

 

15. Feed dog: This consists of a set of teeth fitted below the needle plate. It helps to move the cloth forward while sewing.

 

16. Face plate: A cover which on removal gives access to the oiling points on the needle bar, presser bar and take-up lever.

 

17. Spool pin for bobbin winding: Spool of thread is placed on this at the time of bobbin winding.

 

Other important parts of the sewing machine.

 

a)     Shuttle: used for holding bobbin and bobbin case which carries the lower thread.

b)    Bobbin: detachable part of the machine that carries the under thread.

c)     Treadle: the operator treadle or presses this part of machine to move or drive the machine.

d)    Reverse lever: help reversing feed-dog when reinforcing stitches at the start and end of stitching operation.

e)     Stop motion screw: used for stopping needle movement when bobbin winding.

f)     Needle clamp: used for tightening and loosening the needle on the needle bar

g)    Pressure regulating screw: used to regulate the amount of pressure that presser foot exerts on different fabric weights or thickness when stitching.