Ultimaker Extruder Removal screw

It helps to clean the drive shaft after many many successful builds. Center is a M13 hole that encloses the nut.

Its a derivative of http://www.thingiverse.com/thing:8190

http://www.youtube.com/watch?v=TGXkQ0qusIg

http://www.youtube.com/watch?v=ShVZJ9ULa7g