This instructable will show you how to make a K class sorbitol rocket motor (almost an L) with a total impulse of 482 lb sec of thrust; and will show you how to attach it to a shopping cart! Warning! I am not responsible for what you do with your motor!
To make this motor you will need to machine 3 parts on the lathe. I bought some aluminum tubing 2.5'' in diameter and 2.25'' ID for the motor, and some 2.25" stainless steel (304) for the nozzle. Graphite can also be used as the nozzle but wears a bit each use. I also bought some 2.5" dia aluminum for the end plugs. You will also need the appropriate snap rings and O-rings. I have drawings of the parts on CAD and have saved them as jpegs here.