Grand Piano Action Diagram - Function and Nomenclature of Parts

The Inner Workings of One Note
In a Grand Piano:

1. String
2. Damper head
3. Damper felt
4. Damper guide rail
5. Damper wire
6. Hammer
7. Hammer shank
8. Drop screw
9. Hammer flange
10. Main action rail

11. Damper stop rail
12. Damper wire block
13. Damper wire screw
14. Sostenuto rod
15. Backcheck
16. Hammer rest
17. Repetition lever screw
18. Repetition lever flange
19. Repetition lever
20. Hammer knuckle

21. Repetition lever button
22. Wippen spoon
23. Combination jack & repetition lever spring
24. Wippen
25. Jack regulating button
26. Jack regulating screw
27. Let-off regulating screw
28. Let-off rail
29. Let-off button
30. Let-off button punching

31. Jack
32. Action bracket
33. Damper lift flange
34. Damper lift spring rail
35. Sostenuto tab or lip
36. Damper lever
37. Damper lever key cushion
38. Backcheck wire
39. Wippen flange
40. Wippen rail

41. Wippen cushion
42. Capstan screw
43. Key button
44. Balance rail key pin
45. Key
46. Key stop rail
47. Damper lift rail
48. Back rail
49. Back rail cloth
50. Key frame

51. Balance rail
52. Balance rail bearing
53. Key stop rail prop
54. Front rail key pin
55. Front rail punching
56. Front rail
57. Sostenuto support bracket

Click here to see an upright piano action