I used this arbor to turn down some nuts for my mill a while back but when I made the new 3/4-16 to 5/16-18 arbor I found this in my tool drawer.
Now If I have something chucked up in my little shop I can easily move it to my "big shop" and keep it chucked up in the small chuck.
Whole lotta chuckin going on!
One other tip with this arbor. The threads are long enough that it can be used as a fixed rod stop.