A handfull of collets for things 16682 and/or 16890 !
The ZIP file contains 48 STL to accomodate the drill bits I use the most.
As you can see, there's also collets for hex bits, size 6.25mm face to face.
They work fairly well, check out the pic with the piece of wood, it's a 15mm thick piece of oak and I have been able to go through it with the 1mm bit ! yes, it took me a while ;-)
Get the collet you need from the ZIP file or use the OpenSCAD script to generate another one with a different size.
Metric sizes only -sorry- 1mm 1.5mm 2mm 2.5mm 3mm 3.2mm 3.5mm 4mm 4.5mm 4.8mm 5mm 6mm 6.5mm and 8mm
Everything is provided with 3 different gap/tolerance values: 0.10, 0.25 and 0.50 mm
The OpenSCAD has not been much tested, some features are not even finish... oups!
Anyway, for drill bits (cylindrical) and hex bits should work quite fine.