Tiny Flex Extruder

This is a very simple Direct-Drive Extruder for 1.75mm Filament optimized for Flexible Filaments and easy Filament change.

For a Bowden version see:http://www.thingiverse.com/thing:636178
For a smaller NEMA14 version see: http://www.thingiverse.com/thing:643582

Other required parts:
Merlin Hotend: http://reprap.org/wiki/Merlin_Hotend
Drive Gear 8mm OD 13mm length: http://reprapteile.de/mechanisch/direct-drive-geraendelter-pulley-drive-gear.html
Nema 17 Motor
624 Bearing
2x M3x12
1x M3x25
1x M4x10
1x Spring 7mm OD 30mm length

40x40mm Fan (sleeve bearing recommended)
Screws for the fan

Update 2015-03-06: Made the fan mount holes go through the block to allow longer screws for more stability