This is a lightweight flexible shaft extruder, that i designed for highspeed printing. The idea was to keep the stepper away from the moving parts so not too much mass has to be accelerated without the disadvantages of a bowden-extruder. (i posted a early idea of ot here http://www.thingiverse.com/thing:6653) Another idea was to replace the passive idler bearing with a active second hobbed-thing as well as using gears with a bigger diameter to garanty better grip when extruding at high speed. Also the distance between the gears and the nozzle is relativel short for more direct drive. The extreuder consists of two parts, each of which can rotate around the worm-axis. this way the distance between the worm and the gears always stays the same, but the pressure for driving the filament can be adjusted. The name slugstruder is because of two reasons. in germany we call wormgears something like snail-gears (Schneckengetriebe) and slugs are something like snails as well. Another reason is that i like brainslugs ;) The flex-shaft i will use is one from a motorbike - speedo. These have one prefered direction to rotatet, so be sure to pick one that has the same rotation as the worm gear that u're using. If the torque for thsi one is not enough i will try a dremel like one later. This is a work in progress. The parts i added are only to take a look at the design and do not work till now (the spring tensioner thing and some holes are still missing) also the connection to the flexshaft is missing.. The gears are some standard parts that should be available everywhere. The bigger holes are teardrop shaped to improve printability, but i could also supply some files with round holes.