Building a CNC Milling Machine the Hard Way

CNC conversion for a standard milling machineCurrent CNC milling machines have dramatically advanced what a builder can create from a simple block of metal, and as we've seen, a properly programmed high end mill can turn out amazing work. Home machinists and builders often make do with more basic equipment allowing them to make those special one off parts or even a series of parts, but if you start with a basic milling machine and then get the urge to do CNC work, you have to make a choice, trade it in for a factory built CNC machine, buy some sort of add on kit or design and build everything necessary and convert it yourself. Though the last route is a bit over the top, Joel Miller of Massachusetts, an industrial designer by day, decided to see what it would take to do just that and forged ahead.

Joel bought a Grizzly G0704, a manual machine of the type you might find in a home shop, and set it up in his garage. After getting the feel of it and seeing what it could do, he launched into the conversion, buying parts, metal enclosures, stepper motors, switches and wiring and even designing and etching his own printed circuit boards.

He has a detailed series of posts on his website describing the whole process finishing with some videos of the machine in action, definitely worth your time. I can imagine someone seeing the CNC mill in his garage and assuming it was something he bought as a complete outfit, never imagining he did so much of the work himself. This is "hands on" on a higher level. Nice job!

Link: CNC Machine conversion via Make


  1. AlwaysOnTwo says

    Okay, I learned something here.

    First off, there’s definitely a huge load of the DIY mentality in this guy, and a knack for getting it done. And a level of skill and craftsmanship that is, well, a bit above average. Okay, maybe a lot above average.

    In reading his site, and then visiting a few Grizzly sites, I am rather amazed that there are actually kits available to do this conversion. And apparently, a whole separate “user group” of people that not only are enamored with this particular machine, but hip deep in designing and building similar tooling. Some appear to have the same zealousness for the design and creation process as a bike builder that creates a custom and then parks it, never to be ridden.

    My hat is off to this guy, and his league.

  2. B*A*M*F says

    This is a pretty ambitious undertaking. I’ve looked into it a little bit, and there is a lot to the process. A guy I work with made his own CNC router using a kit of parts and made the frame out of MDF. It was pretty small, and was ok until he tried machining aluminum with it.

    The thing I’ve discovered about CNC machines from using them is that as often as not, the software you use to generate machine code makes a huge difference in quality. We went from a very basic 2D software to a 3D milling program that integrates into our 3D modeling program. The improvements we saw were pretty astounding. The surface finish of the bottom of a pocketed feature instantly became much more uniform and consistent in depth. Ramping bits into material instead of drilling down and then going into cutting has given us much better edge cuts. This bit of software was about $5,000. Our 3D modeling software was somewhere around that, and both programs have subscription services that represent substantial amounts of money for the average hobbyist.

    The software running the machine itself also has a major impact. If your machine’s software does a poor job accelerating and decelerating, corners will be wonky, and machined faces will have tons of chatter marks.

    After that though, the hardware really becomes the driving factor in terms of rigidity of the machine, power of the steppers or servos, etc.

    It’s cool to see more people doing this kind of thing on their own, because it does mean that CAD/CAM software are becoming more widely used. Therefore the software will become more user friendly and the user interface will be less “designed by engineer” (I’m looking at you, SolidWorks). Hopefully, it will also get cheaper.

      • Wave says

        No, Catia is just designed by the French! It’s as typically quirky as an old Citroen. I actually quite like it!

        • FREEMAN says

          The real catcher though is that both Solidworks and CATIA are developed by Dassault Systèmes.

      • B*A*M*F says

        I haven’t messed with that yet, but I’ve heard it’s a bit esoteric in its interface.

        I’ve been using SolidWorks for about 10 years now, and it’s a very powerful and amazing program, but it’s decidedly quirky. Being an industrial designer, I also use software like the Adobe Creative Suite.

        • B*A*M*F says

          I hit reply too quickly. I was saying that Adobe’s interface is more elegantly suited to it’s functions, and more deeply integrated throughout the programs than what I see in SolidWorks.

  3. says

    I did a similar conversion on my mill about 6 or 7 years ago and it still runs strong.
    I get excellent accuracy and perfect repeatability ( at the sacrifice of raw speed ) . My parts always turn out top notch professional . I call it my my mad max cnc machine.
    I read about hobby CNC for several years before I obtained the mill so once I got a suitable mill I had my plan in place and it only took a couple of months before I was making chips.
    Had to learn machine code and purchase some software here and there if you are well versed in CAD then you will not have a problem.
    All this info is out there thanks to people like Joel Miller who are willing to help and share their knoledge.
    I would like to thank you personally for being my silent engineer.

  4. todd says

    Fun. I have access to a number of different manual mills and lathes, which I only use for modifications or simple parts. When I want something to look nice and it has complex geometry or a need a bunch of identical pieces I send off a 3D file to a local guy who turns it around for $50 in a couple days. This looks like a fun hobby exercise but if you seriously want to get parts made you go with the path of least resistance.


    • GenWaylaid says

      I suppose I’m more of a “path of least resistance” guy, too. While I admire the skill behind a complicated build like this, I would admire the build itself if it had a clear raison d’etre. All it takes is “I want to do X, which off the shelf solutions cannot do.” X can be as simple as “cost less than $Y.”