This is a blatant rip off this http://www.thingiverse.com/thing:156860/#files But I've developed it myself using openscadModify the variables in the first part of the script. Mine is setup for my printer which still has some minor calibration issues. I use 3/8 "push fit" connector for my bowden tube. I've made on and it works ok. I'm working on one that includes 2 fan mounts.