I love building stuff – but honestly, i’m kinda lazy. For years i’ve been looking forward to the day when i could design something on a napkin, model it in the computer, then have a machine cut out all the bits for me to assemble.  I wouldn’t have to measure, deal with wobbly cuts or wrangle huge metal blades.  Now, i’ve finally  been able to design and build a CNC Router that helps me do just that.

my homebuilt cnc router.

I should point out this is not a new invention or even a very original design – i scoured the internets and found others that had done similar things and incorporated the features that i liked. One website that was tremendously helpful was  BuildYourCNC.com, which provided most of the mechanical and electrical parts all in one place for really good prices. Also, i wanted the frame to be nice and stiff and as accurate and easy to assemble as  possible, so i borrowed an idea from Joe’s Hybrid 4×4 CNC Router and used 8020 extruded aluminum. I got the 8020 as surplus from 8020′s ebay store with some pretty good discounts.  A few extra trips to Home Depot later and i had all the parts and was ready to assemble.

original 3D model of cnc router design.

A lot of the homebuilt CNC routers or mills i found online were smaller, tabletop affairs. Many of these are great and honestly would have made my project quite a bit easier and cheaper. But i really wanted a machine big enough to handle materials large enough for human or outdoor scale projects. I wanted to be able to make thing like chairs or tables or planters or bicycle trailers – but also i wanted it to be precise enough to do small detailed things like circuit boards or 3d models. Also, I wanted to design my object, shove  a standard sheet of plywood under the router and hit ‘make it!’ and start routing away. All these reasons evolved my Router design into the 4′ x 4′ chain driven model you see above.

Some aspects of my design that differ from Joe’s 4×4 design are the Chain Drive and the V-Groove bearings on aluminum rails, both inspired by the BuildYourCNC folks. Joe’s uses leadscrews or rack and pinion gearing – which both seem great and reliable methods. But after looking at prices for those components online, i decided to use 1/4 inch roller chain, held in tension, traversed by a sprocket mounted to my motor. According to the BuildYourCNC guys, this can eliminate most if not all of the backlash you see in rigid systems and offers good resolution and precision. It seems to be working pretty well so far – time will tell! Also, the BYCNC people sell a very nice V-Groove bearing – that is a roller bearing with a ‘V’ shaped channel cut into it’s hardened steel circumference. Normally these ride on special hardened v-shaped rails, but when talking with the BYCNC guys, they said their experience was by letting the hard v-groove bearings ride on the edges of standard extruded aluminum angle, the bearing traveling back and forth sort of ‘cold rolls’ the rails into the v shape, hardening them and polishing them. It seems to work great, the only downside being as the rails get ‘rolled’ down, the bearings need to be adjusted so they continue to make firm contact with the shrinking rails.

Ultimately. I want to make this the ultimate computer controlled multi-machine tool. Something that has a robotic toolhead that can automatically grab various tools to complete different tasks. Tools that come to mind besides the  router are: Plasma Cutter (for more easily cutting heavy metal), a 3D extrusion print head (that can print objects out of deposited molten thermoplastic), a Vinyl Cutter(for cutting adhesive vinyl for signs, graphics, decals), a Cloth Cutter (for cutting out cloth patterns to sew), and a Laser Cutter head for cutting papers and laser engraving.  a Pick and Place tool might be neat for moving things around, and assembling cut parts. And i’m sure i’ll think of other uses too.

The router works and does a pretty decent job to boot. There already a bunch of upgrades i would like to add (though most would say important things missing!).  Those things include a cable support arm, a dust skirt and dust collection hose, a more appropriate, variable speed spindle (thinking about a Kress 800FME), a proper emergency stop button, limit/homing switches and a depth probe. One day when i’m rich it would be neat to add a 4th and 5th axis! But for now, surprisingly, even with all it’s lacking, the router is fairly accurate and robust and i’ve used it to crank out several nice pieces of work – mostly of the engraved sign variety, but also some unique shelves and table top sorts of things. Check out the build video (coming soon!) and detail pics below and check back for more projects produced on the CNC Router and to see how it grows and evolves.