Strong Greg's Extruder

Extruder based on http://www.thingiverse.com/thing:456025
I have added the hole for J-Head and some screw holes to keep JHeads fixed.
This part is for 3mm filaments
You will need to generate support to print this part.
I liked this part because it's strong between the 2 ball bearings. I have already broken 2 extruders exactly on this specific spot and this design was the one i was looking for except that i needed the hole for the hot end.