Great design, easy and quick access, plus most importantly filament support between the hobbed shaft and the top of the hot end. Good to stop softer filaments from buckling. I lined the printed plastic support with PTFE tube and lined the upper threaded brass part of the hot end with this tube too (See last 3 pictures). Now I can print at 60mm/s with 1.75mm Filaflex, see http://youtu.be/4YCxA04be8w
Many thanks for this JackT.