As a part of The Machine I'm working on, I've experimented with a few choices for driving the head roller. This is a proof-of-concept test with a worm gear made from PVC pipe, with another PVC pipe cut in a spiral and wrapped around. The gears were cut out of second hand cutting boards (1/2" thick HDPE) using the template creator at woodgears.com. You can read more about the machine process at seamlyne.com/blog
