Documentation grand piano by Gregor Deiss, 1815

Exact surveying establishes a reference for reconstruktion of the instrument and therefore requires utmost exactitude and precision. A first step is visual inspection for planning the proceedings of survey. For the Deiß grand a combination of procedures is used:
  • tactile measuring using a Faro 7 links 3D scan arm:

        - with straight tip for locating tuning, bar and end pins

         - with angled tip for components not accessible otherwise

         - with ball tip for measuring the case

  • x-ray tomography for 3D survey of resonance elements (soundboard, ribs, struts, joints)
  • boriscopic survey (position and basic measuring of struts, traces of tools and work processes, materials)
  • laserscan of the karyatids
  • self made measuring rod for a preliminary survey of the internal resonance chamber

Faro scan Arm

Measuring arrangement for tactile surveying of upper surfaces, achieving a tolerance of 0,08 mm. Of particular importance is the exact  measuring of bridge pin positions to  establish the scale lengths in relation to the soundboard.

The result is a 1:1 plan in Rhinozerus CAD. This plan is fundament for replication, can be scaled for corrections and can be printed. 


base board, levers removed

measuring baseboard, levers included


levers prepared for measuring

measuring setting


detail. lever bearing



investigating the resonance chamber using extant apertures

preliminary reconstruction of the inside struts


main struts

  seat of upper struts





laserscanning the karyatids, necessary for all four of them since they are different from each other

a scan in Rhino CAD. For other purposes the karyatids could be made using a 3D printer or a CNC milling machine.



documenting dimensions
documenting dimensions

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