I decided to build another cello but with a few differences from the previous 4 which were all to the same pattern. For this one I decided to re-draw the plate outline based on the Cremona school 5 circles approach with a few tweaks to give me control on where to position the lower corners using the FreeCAD Part Design workbench. I also redrew the f-holes and positioned so them so the centre portions were slightly angled from vertical and using a system that allowed me to position them easily/accurately on the finished top plate.
Main dimensions are:
Body length: 752mm
Upper bout: 350mm
C-Bout: 237.5mm
Lower bout: 435mm
Rib depth at base: 119mm
Rib depth at heel: 115mm
String length: 690mm
F-stop: 400mm
Fingerboard length: 580mm
Overstand: 22mm
Outlines were exporting as dxf files to my CAM system so I could cut out templates on my CNC router. Using FreeCAD also enabled me to 3D print some accurately shaped cauls which were used for clamping up the bouts at the corners.
As the outline was new I also had to build a new form which I designed to be collapsible to make it easier to extract once the back plate had been glued in place.
The finished instrument came in very light at 2840g all up and is very responsive with a beautiful tone and very easy to play.
I have decided to call her “Ella”.
The build can be seen in the gallery below: