![background image](/i/singer/168147/singer-heavy-duty-4423/h/singer-heavy-duty-4423-006.png)
3
16. Horizontal spool pin
17. Bobbin winding spindle
18. Hole for second spool pin
19. Handwheel
20. Buttonhole stitch balance adjustment slot
21. Power and light switch
22. Main plug socket
23. Bobbin thread guide
24. Upper thread guide
25. Face plate
26. Handle
27. Presser foot lifter
28.
29. Foot speed control
30. Power cord
Drop feed control
29
30
25
26
28
23
24
27
20
21
22
16
17
19
18
Principal Parts of the Machine