When I do the small square bowls I enjoy so much, I've started to use some chuck insert rings, and I make them myself, because I'm cheap, and they are easy to make.
I use cheap cutting board for this...
I cut pieces that are 5.5 cm square
Mark the center and then with a forstner bit I drill about 1/4" deep (6mm)
Attachment 44184 Attachment 44185 Attachment 44186
Then using my pin jaws on my Nova G3 chuck, I mount and turn the pieces round, for this whole operation, I only use my parting tool.
In this case just about 5cm, which is just over what my SN2 chuck with the standard jaws will hold. Notice that I mount the piece with the hole from the forstner bit inside, towards the headstock of the lathe.
I turn it so the center piece pops out then I make the step that is about 1/4" deep or so, that will softly and gently grab the tenon on a work piece, without marking it up like the regular steel jaws would.
I then remove it from the lathe and cut a slot in it, the piece I remove is about 1/8" or so.
Back mounted in the chuck, you can see that if you put a tenon in there you can just snug up on it and hold it tight, while not marking the tenon.
I learned this from Eli Avisera of Israel, it is a super cool little trick and dead easy to make a bunch of different sizes for different projects.