The Knight iron frame offers twice the strength of those in an average piano. It is a full-perimeter frame built on a girder principle that is secured to a four-post beech back. The pin block is fitted in a pocket cast into the frame for exceptional tuning stability.
There is no treble stress bar in the K10 model. Several resisting bars are cast in the bottom left-hand corner of the piano to resist the strings’ tension, eliminating the possibility of weak-sounding notes.
Hard fiber plate bushing are used to support the tuning pins to enhance tuning stability. The bass strings are covered with extra heavy pure copper, giving a total weight of 7 lbs(3kgs) a set.
Dates and serial numbers when the pianos were manufactured
| 1855 | 420 |
| 1860 | 960 |
| 1870 | 3200 |
| 1880 | 7900 |
| 1890 | 18500 |
| 1900 | 30000 |
| 1910 | 50800 |
| 1920 | 67500 |
| 1930 | 76000 |
| 1940 | 76400 |
| 1950 | 77100 |
| 1960 | 86000 |
| 1970 | 150000 |
| 1980 | 175000 |
| 1990 | 200000 |
| 2000 | 209960 |
