Compact geared extruder for vertical X axis

This is my new extruder design for the Heavy Mendel :


It's more compact than my previous extruder and mostly made with printed parts, the last one was made from milled parts.

The sub-d cover is also printed :


More details about the full-metal hot-end :
The heater is made from an M6 insert with the external thread removed :
[reprap.org]

The tip is an acorn nut drilled with a 0,5mm drill-bit :
[reprap.org]
and hammered to reduce the hole size : [PIC]
[reprap.org]

To keep the entrance of the hot-end cold, an assembly of aluminum plates and brass nuts forms a heat sink :
[reprap.org]

Stl files and sketchup assembly are available on the Heavy Mendel wiki page : [reprap.org]

I tested different shape of nozzle :

Round (acorn nut untouched), cone at 120° angle, and 90°angle

To test the nozzles, I printed A 60°overhang in PLA whith 0.1mm layer height :


The round nozzle is the worst, 120° and 90° give the same result.

This is very interesting. What was the Width / Thickness ratio for the prints?

Is it possible to provide some close up pictures showing details of the laid threads?