Collet Chuck Extension Tool for C8-ER11A-150L sourced from http://reboots.g-cipher.net/spindle/index.html
The CAD was made using Solvespace for simplicity, https://solvespace.com/index.pl .
All rights belong to the designer of the part.
I just re-designed it in Solvespace as a learning exercise while exploring an alternative minimalist CAD.