The collet holder is for these collets. The handle holder is for this handle. Which go together, so it all works out! :) Printed in PLA.
The handle holder needs supports, and the part that is inserted into the handle may need to be sanded down a little, or possibly printed at a lower layer height than I did (0.25mm), to minimize the stair-step effect.
The text on the collet holder was added in the .3mf, so if you don't like my choices you can just print the blank .stl or make your own text. And, if you would like more/less slots for collets, I have included the OpenSCAD file.
The author remixed this model.
Both holders use inserts from the OpenSCAD library.