While this is true. I have found some 801s that short when connected to the adapters (especially the newer adapters)*. If the 801 is your primary atty, you might just want to go ahead and get the 801 chuck. Then you can still get the adapters to go from 801 to 510 or 801 to 901/(808) later**. That way you don't have to worry about shorting issues for you main attys.
* Some of the newer 510 to 801 adapters have a thicker outside ring that touches(shorts) the center pin of the atty
** Jeff does not sell adapters to go
from 801 to other models. You will have to get them elsewhere (heaven gifts carries them).