A lot of the small mini lathes have a flange attached to the spindle and 3-4 bolts that hold the chuck on with a alignment ring in the flange. but no taper in the spindle, this taper is extremely useful to mount tools and fixtures and is much more accurate than the chuck.
On my minii removing and replacing the chuck takes some indicating and tapping to get it right. The 3 jaw is good for about .005 as it came.