Here's my 15 year old one and the same thing for sale online-
Attachment 364301Attachment 364302
--other than different stickers and some safety guards (ahem ;) ) they're virtually the same.
The jaws on this chuck work in the fiber's chuck (and vice versa) perfectly. Now, whether you can buy just a chuck from HF I'm not sure but I'm sure you could get one easy enough somewhere. Making it fit anything you want is a matter of machining a new back plate for the chuck that the other end of fits your Epi rotary. My V3400 cylinder machine has a 5" chuck that was too big for a certain job many years ago, I just made a pair of aluminum adapter plates that allowed me to swap the chucks.