The new J-Head Hotend V5 is shorter than my Printrbot Ubis Hotend. So I made this adapter to extend the length.
I haven't mounted this yet, but holding it next to my (printing) bot, it is a smidgen longer than the original. You could take a few mm off the length, but it was close enough for me.
The nose needs to be a bit bigger though ;)
Could possibly be used for other Hotends (?)
EDIT Wrong STL - Hang on... fixed!
(Trivia - if you Export as STL before Compiling, OpenSCAD exports the last file you compiled :| )
Print. I used 1 perimiter 2 layers (0.4mm) and 20% in-fill. Concentric in-fill was 'interesting'. Less is more.
As it is a bit tight it helps to push in the Nozzel while it is still warm with some force. Then remove.
Cleanup small end and the holes with M3-ish drill. Don't forget center hole.
Insert Nozzel into adapter & adapter into extruder and secure with M3-ish screws.