Bosch chuck removal

Grandpa, after discussing removal of the chuck mechanism with you, I tried and tried, went through my entire collection of stars and squares looking for the right combo to "remove" the inside screw and the rest would follow. After looking it over and almost 86ing it, i noticed a small hole at the base(behind the chuck that ran entirely through the body, the shaft and outside the other direction. Putting a small bar through the hole and then turning the chuck manually, off came thr chuck in a matter of seconds. So, it must depend on the model number you have wether or not you need to remove an inside hex/or lock the shaft in place and unscrew manually. Point being, thanks for the advice. You got me started on the right path. Heres a few photos to give you an idea...