That spit driver is an engineering marvel, the way a seemingly disparate set of pulleys and shafts has been manipulated through so few combinations and connections to give the correct output speed......... I assume its only a single speed or is it a multi-speed unit? AND, the portability, they just don't make em like that any more!
Only kidding! I'm envious of it, haven't yet managed to build a spit, although I could probably find enough shit lying around my shed(s) to do something ingenious.
Have just finished a BIG brick oven which could hold a suckling pig though!