At last, the Mostly Printed CNC provides a low cost entry point to DIY CNC.

After largely mastering basic 3D printing, I have spent the few months considering how to explore basic CNC machining. The other day, while browsing Thingiverse, I stumbled across the Mostly Printed CNC. Wow! This might be what I was looking for.

If you want to follow along, here are links to the Mostly Printed CNC web site and file repository on Thingiverse.

While there are a lot of similarities between 3D printing and CNC routing/milling, there are a lot of differences:

• Both can work using a similar Cartesian motion framework – X, Y and Z axis – and linear motion using stepper motors. Both can use a combination of screw or timing belt drives.
• CNC machines must be stronger than 3D printers and be able to handle much more torque.
• DIY CNC machines typically use specialized controller boards often seeking a parallel port (remember them?) rather than USB. This is desired for the fastest communication between computer and machine.

Why I selected the Mostly Printed CNC

The criteria I set for choosing a starting design were as follows, along with a description of how these appear to be met by the Mostly Printed CNC.

• Low Cost. I set a budget of US$500. There are many DIY or Desktop CNC machine kits available between US$1200-US$2500, but that was too much for a retired guy to get started. I should be able to build the Mostly Printed CNC for around US$300 because I already have some of the components.
• Simple, readily available parts and components. The Mostly Printed CNC runs on 3/4” steel conduit (EMT) held together by plastic structural connectors that can be 3D printed. Everything in the design is readily available on eBay, Amazon or Home Depot.
• Proven Design and Wide User Group. The Mostly Printed CNC design appears to work surprisingly well and has won several awards. There are dozens of videos on You Tube of the design in action. Parts kits are available and there is an active user group.
• Build using my existing knowledge, skills and tools. Expensive custom-fabrication is not required. There is no need to have special wood, aluminum or acrylic plates machined. Basically, the frame can be fabricated using my 3D printer, a pipe cutter and a wrench. I can use an Arduino, a RAMPS board and Marlin firmware to get started. My initial machining can be done using my rotary tool (Dremel).

So, there you have it. My new project. Perhaps foolishly, I am so confident that I can successfully build this machine, I am going to document the build on this web site as I go along. Win or lose, you will have a front row seat.