Extruder number 1

Until I ahve my new PSU, I decided to assemble my Bowden Airstripper extruder ; I’ve chosen to replace the diesel hose by springs (After different trials of some types of spring, I finally decided to cut some loops in order to fit a correct length – the stiffness topic will be treated afterward).


In a first step, I noticed that the motor axis has no flat surface; a file plus a little bit of elbow grease and the business is done (all that fuss to save one machining step  😕 ) :

extruder_flat_surface1 extruder_flat_surface2

Motor axis with its new flat surface
view 1

Motor axis with its new flat surface
view 2


I assemble the Mk8 gear, the MR105ZZ and 608ZZ ball bearings, the 8 mm diameter axis recovered from a stub bar and the printed parts; non negligible dexterity is required to mount the washers and the nuts at the tip of the M3 screws with the springs:

extruder1 extruder3

Assembled extruder
view 1

Assembled extruder
view 2

extruder2  extruder_Mk8_gear

Assembled extruder
view 3

(motor with just the gear
and the ball bearing)


In retrospect I find this extruder inconvenient (but nevertheless it looked quite “pretty” on the CAD file); I anticipate some set-up issues and in-use consequently … in short I’m skeptic.


I’m looking to have a new extruder at hand, like this one or this one for example …. to see later!


On the Reprap forum, Fourmi shared its extruder that you can see below; it is composed of only 2 parts. Nevertheless it requires a 686ZZ ball bearing whereas I’ve plenty of 608ZZ (bigger part), so I’ve to make some changes to use one of them.


Original design :

  • 4 FHC M3x15 mm screws
  • 1 CHC M6x10 mm screw
  • 1 686 ZZ ball bearing


I’ve added his STL files