Davinci x belt manual tensioner - standard pulley

The standard item has a spring and a pathetic screw to keep the tension on the belt. I found the screw would tire and then the belt would loosen under load as the spring let it go.

This is a remix of the belt tensioner http://www.thingiverse.com/thing:690090 that uses the original spring to tension the the stock pulley.

This version uses an M6 bolt through the end, it's much easier to fit - Simply loosen the bolt right off, push it all the way in, slot the idler pulley in on the belt and