Keywords: Zumpe english single square action.svg Zumpe's or Masons action drawn from the instrument of 1766 traced and colorized by Mireut from figure 6 page 715 George Grove ed A Dictionary of Music and Musicians vol 2 MacMillan and Co London 1880 http //www archive org/details/musicians02grovuoft 1880 A J Hipkins key 1 <br />jack a wire with leather stud on top known by the workmen as the 'old man's head' 2 <br />whalebone rear guide projects from the end of the key works in a groove to keep the key steady 3 <br />hammer 4 <br />whalebone jack called the 'mopstick' 5 <br />damper 6 <br />whalebone damper spring 7 PD-old Musical instruments schemes Musical instruments technical diagrams Piano action Square pianos Diagrams labelled with numbers only SVG music |