A scroll chuck is an adjustable set of jaws attached to the lathe spindle at the headstock. It holds and spins one end of the wood while you are turning without support at the tailstock. For your safety, always support the wood with the tailstock until it is time to hollow the piece. Scroll chucks come in many sizes. Select a chuck that matches the lathe you are using. Several types of jaws are also available for a variety of woodturning projects.
While a chuck is something you will probably want to have, they are fairly expensive and it is not necessary to buy one immediately. You can turn wood between centers or by attaching it to the faceplate that came with your lathe using wood screws. NEVER use drywall screws. Another option is a glue block attached to a faceplate; attach to your wood with hot glue. When turning small projects this is an excellent option.
A jam chuck. It consists of a piece of wood secured to the lathe spindle using a scroll chuck, a faceplate or a threaded adapter. The piece of wood has a hole or groove turned into it that is the same size or slightly smaller than the piece you are turning. Your project piece is then literally jammed tight into the hole or groove. This method can be used to finish a bowl bottom or finish a finial.
A vacuum chuck. This chuck consists of a vacuum pump, pressure gauge, tubing and adapter. It is used to hold your work firmly for things like finishing the bottom without damaging the finished side of your work