Flexible extruder for E3D_V6

optimized for flexible filament.

e3d v6

extruder gear : http://www.aliexpress.com/item/3D-Printer-accessories-Extruder-Drive-Gear-1-75mm-Bore-5mm-Stainless-steel-Feeding-Wheel-Squeeze-Feed/32581730475.html?spm=2114.30010308.3.154.oBIOnF&ws_ab_test=searchweb201556_2,searchweb201644_3_505_506_503_504_301_10020_502_10001_10002_10017_10010_10005_10006_10011_10003_10021_10004_10022_10009_10008_10018_10019,searchweb201560_2,searchweb1451318400_-1,searchweb1451318411_6448&btsid=fcf4819e-fdb2-447b-b366-d3ad2b747709

bearing : od 11mm id 5mm