Universal CNC Axis

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  • The Universal Axis is a modular and scalable (easy to 200 lb tool force at 10 micron precision, larger with modifications on the basic system) CNC axis which can be used to create cartesian CNC machines. We have so far prototyped 8 mm, 1", and 2" rod versions of this. The core of the axis is belt drive and linear motion rods where carriages are pulled on the rods. The axis system may be used for the X, Y, and Z axes of cartesian robot system. The system is scalable to any size and number of axes. Rotary axes may also be used with this system The system uses a combination of 3D printed parts, metal plates, and belt-driven shafts. Applications include 3D printers, CNC torch tables, heavy duty CNC machines, and many other production machines.
  • Both the belts, drive pulleys, and linear bearings may be 3D printed. This remains as future work.
  • Force limits - the universal axis does 50 lb precision force (10 micron resolution using 16 microstepping and 1/2" diameter pulleys) per 15 mm wide high precision GT2 belt strand with nema 23 motors. So in practice we can safely get up to 600 lb of precision drive force if we use 2-sided drive (like Y1 + Y2), 2 motors per axis, 3 belts per axis. Screws can be used for higher force. If we want more than 600 lb force with belts, we could use belts other than the tiny GT2 belts.
  • Applications - precision machining, automation, digital fabrication construction sets. A generic platform for precision motion and linear actuation.


See Universal Axis Development Template

5/16" Universal Axis

There are 14 unique parts in the Universal Axis:


We have built up to a 2 Meter Tall 3D Printer and a 1 cubic meter 3D printer using the 8 mm (5/16") Universal Axis:


Simplification - From Clamshell to 1 Piece

See Universal Axis v20.07


Part Library

See Universal Axis v20.07 3D CAD

Applications of 5/16" or 8 mm Universal Axis So Far

1" Universal Axis

See 1" Universal Axis

So far it was used to prototope a CNC Torch Table in 2018:

It interoperates with the 8 mm axis:

We also built the CNC torch table in 2019 - CNC Torch Table v19.10, and in 2021 - CNC Torch Table v21.08.

2" Universal Axis

See 2" Universal Axis.

Universal Axis Development Directions

Current Work - Universal Axis Designer in FreeCAD

See Universal Axis Designer in FreeCAD.

Future Work


Example of CNC Circuit Mill Configuration, 5/16" Axis

See full documentation at D3D CNC Circuit Mill


The following is a 5/16" or 8 mm version of the universal CNC axis described at http://opensourceecology.org/3d-printer-construction-set-workshop/

Larger axes will also be built, up to 2" for heavy duty CNC machining, with plastic parts sandwiched between metal plate as a plastic/metal composite structure. See calculations for beam deflection at Heavy_Duty_CNC_Construction_Set.

Universal Axis - Working Document







From Michel Dhoore in Belgium in 2016. Early prototype using larger carriage pieces for larger machines.









Frame Parts



FreeCAD and STL Files for Printing

See 3D Printer Part Library for all printer parts.

Originals from 2016 by Michel Dhoore

This file has the carriage belt tensioners, not shown below.

Universal Axis with Magnet Holes 2017

HintLightbulb.png Hint: Under development Feb 2017


  • Print time - 3hr27min for the idler end -


Belt Tensioning

One Axis Attached to Frame

See Also


Industry Standards

  • This one appears to be open source - [1], but has about 4x the unique count and lacks scalability and right angle connection ability.