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Libro Struder

Release status: Experimental

Description The LibroStruder is a non-slip filament extrusion mechanism that uses plastic on plastic friction instead of a metal hobbed wheel.
License GPL
Author David Hartkop
Based-on Delta
Categories extruder
CAD Models
External Link on thingiverse

About the Libro Struder

The Libro-Struder is an original 3d printer extruder created for the Pueblo City-County Library District by David Hartkop. It is part of the RepRap Libro project but is a general purpose filament extruder for all your filament-pushing needs. It uses plastic-on-plastic friction forces rather than toothed-gear biting forces to grip and advance a plastic filament. The Libro-Struder is less prone to jamming and slipping than the more common Wade or Bowden-type extruders. It can also be created with fewer specialized parts. The design explores the idea of using taken-apart pop rivets as tiny bushings on shafts. The current model does require a stepper motor that has an orbital gearbox attached. I have had much success with a Nema 17 stepper with a 27:1 gearbox, Part No. 17HS19-1684S-PG27.

Hackers encouraged to print their own gearbox. :-)


Nema 17 motor, 27:1 gearbox #17HS19-1684S-PG27

4 x M3x8mm screws

Push-in pneumatic fitting for 4mm od nylon tube

18 gage steel wire, 3 inches

22 x 1/8” x 1/4” long pop rivets, steel.

nut #10 (M5)

set screw #10 x 3/16" long (M5x5mm long).

Printed Parts:





All printed parts can be downloaded from [1] on

Videos of LibroStruder in action:

See video of printing a Pyramid: [[2]]

See video of printing a part for the RepRap Libro: [[3]]

See video the Libro-Struder power loading here: [[4]]

See video of the Libro-Struder extruding here: [[5]]

See video of dragging filament out of the Libro-Struder: [[6]]