About this 3D model

The purpose is the same as the Ultimaker Hobbed Bolt Release by bkubicek ( http://www.thingiverse.com/thing:14505 ). However, I have a different kind of hobbed bolt, so his model didn't match my bolt. Also, some nuts didn't allow the holder to turn, so the knurled part is separated from the extruder and the external diameter is slightly lower to fit loosely with the extruder motor.