Re: hollowing tools *LINK*
Lyn J. Mangiameli
>I've recently completed a comprehensive opinionated survey of almost all the hollowing tools commercially offered. The originals are published in More Woodturning, but Fred is gracious enough to make them available as free pdfs at the link below. The first section is probably the one you will be most interested in (there will be five sections in total). At the same link, you will also find several full reviews and user tips for several specific hollowing tools.
As for making your own tools, Darrell Feltmate has some web instructions to make a number of hollowing tools. There are several web sources as well but Darrell's are among the best. You can find them here:
http://www.aroundthewoods.com/
http://www.fholder.com/Woodturning/lyn.html