It has been done, but personally I wouldn’t do so, for the following reasons:
1) The TIR of a 3 jaw chuck probably isn’t that good, and if it is, you shouldn’t be using it for milling!
2) The milling cutter will be much harder than the chuck jaws, so the grip will not be particularly good
3) The jaws will only grip over a small area, compared to a proper milling chuck – see above
4) A largish chuck holding a small endmill increases your chances of getting a bonk on the nose or hand when getting close to see what is going on
No doubt there are many other reasons too. Use an ER style collet chuck, preferably mounted directly on the lathe spindle nose.
Regards,
Andrew
Edit: Of course there’s no reason not to use an end mill in a lathe, just not in a 3 jaw chuck
Edited By Andrew Johnston on 18/10/2010 16:57:34