This thing is a derivative of the following: Paxtruder 0.2 - http://www.thingiverse.com/thing:1125 Paxtruder mount - http://www.thingiverse.com/thing:1341It has been changed to allow the extruder clear the opening in the top of our MakerBot. It also allows for more z travel, as the extruder head is mounted higher.We used PETG instead of acrylic because it is less brittle., but acrylic will work just fine. You will need 3/16\" (.165\") and 1/8\" (.115\") PETG or any similar material.All parts are cut out on a Universal X-660, except for the tension block, which is made of nylon.In addition to parts from the MK4 extruder, you will also need 7 M3x30mm machine screws to mount the pieces to the motor.