I finally made a re-design of the extruder assembly of a Beta
The design was on my mind for a long time.
The advance is the bigger diameter off the "bolt" (20 mm) and a bearing as a pressure roller.
Also the wheel has just straight grooves so I don't have to clean it anymore.
Because the grooves are straight it's not grinding in the filament
I print for many hours without cleaning.
My parts are looking better also because of the constant transit of
The only disadvantage is that you have to make some parts in steel.
Print part and assemble.
Some parts must be mirrored.
The parts 50materialwheel and 50pin-M4 are made of steel.
I use the standard bearings of the Ultimaker 8x16x5 mm.
For the tube I use a standard fitting of Festo.
G1/8 with 6 mm hole.
You have to tap this thread in 50 fittingblock.
Before you print you have to change some settings in the software because of the larger wheel.
With skeinforge >40 set M92 to about 315.
With skeinforge<40 set Flowrate to about 17 when using feedrate 60.
There is also a Solidworks 2012 zipfile with all the parts.
Please comment when things are not clear or wrong.