Basically bore size cannot be changed, you need a lathe with a large enough bore to do the work you intent to use the lathe for.
There are several differences between a metal lathe and a wood lathe, the most important is that wood lathes do not have tool holders with geared movement. The tool in a wood lathe is held over a rest by hand. Tool holders on a metal lathe are bolted in place and have hand cranks to move in/out and left/right.
A cue lathe is simply a lathe adapted to the needs of cue making. It would still be considered a metal lathe although most small custom cue lathes are very light compared to most fabricating metal lathes.
Bob Danielson
www.bdcuesandcomix.com