rack for 8x 20 mm ER collets, engraved 4 mm, 5, 6, 8, 10, 12, 13, 16 mm
Designed with crossplatform GUI parametric C++ FOSS CAD program http://solvespace.com/
Editable designfiles provided in .slvs format.
Solvespace 3.0 outputs STL, STEP and PDF.
Fitting collet parts were sourced from retailer HBM: https://www.hbm-machines.com/nl/p/hbm-iso-30-spantangenset
The author hasn't provided the model origin yet.