After looking through the many mods for makerbot extruder , I actually decided on the makerbot version. Downlaoded it and printed it.. Looked great , pieces fit fine,, didn't have the bearing, the shoulder bolt nor the spring ,, so I made one to fit the qu-bd extruder using the original bolts and a bearing I had on hand. I haven't printed this since revising the mount to include material at the bottom ,, The one I first made is open at the bottom and is trying to spread just a little, but is working fine.This will give some options to lever position as my printer is my own design and the other mods were inaccesable on my setup without changing the extruder mount..