I have a rather generic Asian lathe of 10 inch swing (5 inch in UK money), marketed in Canada by Busy Bee tools
http://busybeetools.ca/cgi-bin/picture10?NTITEM=B2227LThe chuck is held on 3 M8 socket head cap screws, similar to several other brands of lathes. There is little room between the spindle and headstock and required the use of a sawed off hex wrench, much twisting, fussing and cursing and about 15 minutes of time to effect a chuck change.
This made changing chucks too much of a chore and I tended not to change them very often.
I fussed for a bit and a fix came to me while I was sitting on the throne - seems I do a lot thinking (and stinkin') and while sitting on the throne and solve a lot of little problems too!
What I came up with was a replacement for the M8 socket head cap screws that I can turn in and out by hand only needing a wrench to snug up or loosen off. Made from 1/2" 12L14 leaded steel (could be made from any similar size i.e. 12mm). Took all of a bout an hour to make the three needed, threading done on the lathe and still on the original parts made over two years ago. I can now effect a chuck change in under 5 minutes, wrench needed only to loosen to snug up - the remainder screwing in or out easily done with two fingers.
The pictures show all. One photo shows the three replacement bolts along side one of the original cap screws and it's hex wrench. The second photo shows the replacement bolts in situ on the lathe holding the chuck in place.