Mk8 Spring loaded Drive Block Replicator 1 / Duplicator 4 / FlashForge / CTC

Adapted version of ivcs fillament drive block: http://www.thingiverse.com/thing:62510 ___Update:___ _DriveBlockBase V9 allows printing of NinjaFlex and other flex filament and is tested on WanHao Duplicator 4 and CTC Dual with NinjaFlex. Please see attached pictures and read instructions for some tips how to configure your slicer right to not blame the drive block for mistakes you make._ Original idea was to modify it that it can handle bigger draw rolls, like used on Wanhao Duplicator 4, which has a 11mm cylindric gear-wheel with and a 12mm ball bearing draw roll with a grooved surface and a shaft diameter of 3mm. I read a lot of broken ball bearing shafts and because 3mm is a very weak shaft diameter if you use a strong spring I decided to add a M3 pan head screw as shaft instead. In addition all spring loaded drive blocks I know have overhanging ejection units on the outer sides. I think this might disturb some ideas to use the extra head room we have in the printer especial