Dasazer!
Good for you! If you got the mandrel and the live center, you're on the way to turning pens. :D
You can also use the
1/4" router chuck, SS item #514632to put the mandrel in permanently, rather than put it in the jacob's style chuck. Gives you more room for clearances with the tool rest. You may also want to look at the 4" tool rest if you are going to do any lipstick pens. Allows for getting the tool rest closer to your work, not so big a gap between the tool rest and the turning, improves support.
Don't forget to re-grind your lathe chisels as the 5 degree angle on the chisels (standard grind for all chisels) should be opened up to 11-13 degree for better shearing and improved clearances.
Have fun with the pens. :) One chip at a time!!!