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Release status: working

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The RepRap Wiki UConduit page.
Creative Commons Share Alike 3.0
CAD Models
External Link

The UConduit 3D printer is an h-bot 3D printer, with a frame built from electrical conduit (steel conduit that you can find at the hardware store). It is open source hardware via the Creative Commons Share-Alike license. The project is hosted on github [1]. All printed parts are designed using OpenSCAD (an open source CAD environment), so that parts can be freely compiled and modified.


There are many options for framing. Most higher-end 3D printers these days are using aluminum t-slotted extrusion or specialty laser cut parts. While I think these options are achieving excellent results, I wanted to build a printer that also had a solid frame, but went back to the hardware store mentality of the earlier Mendel and Prusa printers. Conduit is extremely inexpensive ($3.50/5ft) and plenty stiff for a printer. It created some extra challenges in design work, but has an additional payoff.

The printer is connected using o-rings and compression flanges. Each end has two rubber o-rings. There is a “hard clamp” and a “soft clamp”. The hard clamped o-ring creates a pivot point and firmly holds the conduit in place. By adding a second “soft clamped” o-ring on each end, vibrations are very effectively damped. As a result, the printer is not only fast, but also super quiet! Wiring can be neatly routed from the top to the bottom of the printer (using the conduit for its intended purpose!).


Designer Lee Miller
Model UConduit
Technology FFF/FDM
Size 485mm (W) x 445mm (L) x 380mm (H)
Weight ?
Max Potential Build Envelope 265mm (W) x 250mm (L) x 240mm (H)
Cost to build $??? US


  • Simple, fast h-bot design format with Marlin firmware support.
  • Low cost, locally source-able framing material.
  • Fully designed in OpenSCAD.
  • Vibration damping built directly into the frame. O-rings and compression flanges tightly connect frame pieces.
  • Internal cable routing neatly routes motor and endstop wires to the bottom of the frame.
  • The 00str00der belt-driven extruder.
  • Solid bearing holders with retaining clip mounts for LM8UU linear bearings.
  • Lightweight gantry with no moving motors on the entire printer -- reduces inertial forces. (Is this a CoreXY-like drive train ?)
  • Oversized printing size in standard design. Simple to scale to larger or smaller formats.
  • Bowden extruder and carriage with push-to-fit connectors. Easily adaptable for use with multiple extruders.
  • GT2 Timing Belt and pulleys used for x-y motion and extrusion.
  • Simple filament spool holder clamps onto the frame. Spool mounts on a separate piece of conduit.


I first began development on the UConduit in September 2012. Since that time, all parts were tested, optimized and revised multiple times. In the current state, each piece of the printer has undergone a minimum of 3 revisions. The printer is fully operational and ready for community use and evaluation.

Printed Parts

All printed parts are available on github[2]. Pictures and additional details are available on the thingiverse page[3]. Support for the UConduit is available on the google groups page[4]. For additional pictures, see the imgur photo gallery[5].



The frame material for the standard build is 3/4" (21mm metric) thin wall steel conduit (electrical metallic tubing, EMT). Note that the OD of 3/4" EMT is not 3/4" (it's actually 0.82" or 20.8mm). This is the "trade size" of the tube, which is equivalent to 21mm trade size EMT[6]. The conduit is connected using size 118 orings(extra soft Buna-N recommended). Support for alternate 20mm tubing is also planned for those who do not have access to EMT.

Build Instructions

At this time, a build guide does not yet exist. There will be a comprehensive build guide in the near future. There is a beta-BOM available on the github repository. A comprehensive set of images will be available in the immediate future for build assistance.


Coming soon!

Future Development

Additional versions including a deluxe version with multiple extruders and a lowest-possible-cost version planned.