1. Key.
2. Jack.
3. Jack-operating spring.
4. Cushion limiting rebound of jack.
5. Button and screw regulating escapement of hammer.
6. Hammer-butt and operating face.
7. Hammer-butt pivot.
8. Hammer-shank.
9. Hammer-head.
10. Check.
11. Damper-lifter.
12. Damper-head.
13. Action-rails.