Left and Right Drive Block for Makerbot Replicator 2x Dual Extruder, it works very well with filaments that have not constant diameter.
file has been Updated with a new version 2
now the teflon tube entry is lower ( 7 mm ) and does not stress the filament or the tube.
Print this file in the same position as downloaded, and only few supports will be created.
the file has big tolerances,so you'll need to use sandpaper only on few details.
The block will reuse all the metal components of the original Drive Block, only the small spring as to be replaced by a bigger spring from a common plastic peg. One of the screw that lock the block has to be cutted to make possible screw until the end.