On May 3, 9:38*pm, Bill Schwab wrote:
So far, I have turned a little Al tubing, and noted that the 3-jaw chuck
(the only one I have used so far) was not running true. *
Bill

3-jaw chucks don't center the work perfectly anyway, and they get
worse as they wear. Their advantage is convenience. Use a 4-jaw for
accuracy and also when you need to tighten the jaws hard.
Jim Wilkins