That’s an ER40 hex collet block mounted in the chuck. The following is quoted from this thread
The motor/driver setup is this novusun 500w spindle. It’s essentially a cnc setup but also has manual controls.
moderator007 suggested the cam wheel idea…
EDIT- I just realized your question about the collet is in relation to the spindle collet. That one is ER8 size.
I have tried a little milling on titanium , i’m not in a rush to do it again . One suggestion I would make is get a larger ER size. You can always put small drill bits in a larger collet but not the other way around.