Thanks for the warning about the bit being too far in.I believe the biggest issues are:
- Having the bit too far in. In that case, some chucks will grab only near the bottom of the bit. A buddy did this and launched a whirling, bouncing bit.
- Not in far enough to be held properly.
The whole O-ring trick is to keep the bit from bottoming out because when the router is upside down it's hard to hold the bit above bottom while tightening.
I think all the replies are right... nothing to be gained beyond a certain depth but keep it off the bottom.