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What do you do when you want a CNC machine but don’t have the room or the funds for the massive professional equipment needed to cut custom parts? I found myself with this dilemma, so I chose to scale down my purchase and invest in a manual mill that I could eventually convert to a CNC. Before purchasing my Mini Mill from TheLittleMachineShop.com, I did some research to investigate what it would take to switch from a manual mill to a complete 3-axis “Computer Numerically Controlled” machine. Many of the popular small hobbyist mills are manufactured in China and Taiwan and then shipped to companies like Harbor Freight, Grizzly, SIEGE and Micro-Mark who paint them various colors and sell them under different names. Since these mills are all based on the same design, a community has formed around this popular mini mill platform to share ideas, hacks, and improvements through forums and a wiki . When opting to convert to CNC, there are numerous kits and conversion designs to choose from that span simple PDFs and wiring diagrams to high precision hardware and ready to run electronics bundles.

CNC Fusion is a small company that machines high quality conversion parts made from 6061 aluminum for small mills and lathes. The company started in 2004 when Michael Rodgers, a machinist by trade, wanted to create a CNC machine but realized that he could not build the parts he designed without first owning a CNC machine. That initial desire has led Michael to design and fabricate CNC conversion kits for small manual mills and lathes, and now his kits are sold around the globe (40% of CNC Fusion production is shipped to overseas customers). The household garage has been converted into a machine shop where Michael machines the majority of the kit components using a large 3 axis SHARP machining center while wife Shelley helps run the large Okuma CNC lathe to machine the ends of the ball screw threads sold with their kits.


With the X2 Mini-Mill CNC kit #2 all the new upgrade parts bolt to existing features and you replace the factory lead screw with high precision ball screws and new motor mount adapters to accept NEMA 23 stepper motors. The hardware installation is very straight forward and requires the disassembly of the X and Y axes before reinstalling the ball screws. The only physical modification to the mill occurs during the installation of the Z axis motor mount, and requires that you drill two 1/4″ holes into the column of the mill. Besides this step, the entire process is completely reversible in case you ever decide to switch back to manual machining (but honestly why would you!)

The electronics are sold separately, but Michael suggested I source the driver board and stepper motors from the company Probotix who offers complete electronics bundle kits for three and four axis machines with a special package designed specifically to fit the X2 Mini Mill. I opted for the Ready to Run electronics bundle which will cost an extra $150 but includes all the additional components that you will need to get your kit operational. (option includes large electronics enclosure, fuses, fans and necessary wires, nuts, bolts…)

I had saved an old Thinkpad laptop just for this project which happened to have a parallel port on the back. If your computer does not have a parallel port, Probotix offers a USB breakout board for an additional $75. I decided to stick with the parallel port connection, but upgraded to the PBX-RF breakout board. This breakout board was designed for hobby CNC machines, and protects the 5V logic portion of the board from the 120V side to ensure that your electronics will not fry if you get a spike or a short circuit from the motor drivers. An added safety feature well worth the initial cost.

A note about using laptops to run the CNC control software from Len at Probotix:

Some years ago they started putting advanced power management features into the bios whose primary purpose seems to be to extend the life of the battery. The problem is that because it runs in bios (under the operating system) it has higher priority than anything the OS is doing. If the bios decides to, for example, check the fan speed while EMC2 needs to be sending a step pulse, it will throw a hiccup into the pulse stream and stall the motors. You may or may not be able to disable this in the bios – even if the bios has that option, the issue may not completely go away. There is a short blurb about it here, and some more info here, and here.

So, before you run out and purchase a new laptop to run your CNC machine, you might want to think about sourcing an old desktop for cheap instead. I have been able to use my Thinkpad to run Mach3, however, I had to Optimize Windows for use with Mach3 following these instructions.

Probotix also offers the RBX-1 3-Channel Opto-Isolated Relay Board which I added to the package. With this board you can turn power on/off to three devices rated for 12Amp at 125VAC. For example, you could control power to the spindle, coolant pump, and vacuum system all from your CNC control program. Note however, the relay cannot control the spindle speed but only turns power on/off. This could be used as a safety feature to automatically turn off power to the spindle while you clamp down your work piece or remove a finished part from the machine.

When my kit arrived, I simply connected the stepper motors to the X,Y, and Z ports on the back of the electronics box, plugged in the power cables, and attached the parallel port serial-port to the laptop. With the electronics connected, I then installed and configured the CNC control software to communicate with the machine. Probotix recommends the free Linux-based EMC2 software package, but the kit will work with other CNC control software including MACH3. You can find example settings for both EMC2 and MACH3 on Probotix’s Support web page.

3-Axis wiring diagram from Probotix

With both of these kits installed, the last step is to fine tune the machine and install any limit switches and emergency stop buttons. Limit switches are not included with the electronics kit, but are not required to run the CNC machine. They are an added safety feature however, and will inevitable prevent you from crashing the machine if you are new to CNC. With everything installed and running it is finally time to design a test part using a CAD program, import the file into a CAM program to generate G-Code, open that file in your CNC control software, secure the metal stock to the table, then run a test cut. Assuming everything was done correctly, you should now be able to design and machine your own custom parts.

Both CNC Fusion and Probotix have great customer support and are very friendly and helpful. I am very impressed with the quality of each of the kits and was amazed at how easy it was to install the hardware components. If you are not comfortable working with electronics, the Ready to Run electronics kit saves time and anxiety. I was able to install the hardware conversion kit and make the first test cut in the same day. The real trick with all of this is learning to use the different CAD, CAM, and CNC controller software packages, and this is where people who are new to CNC may struggle. I am currently working on a tutorial that will show how I hooked up my limit switches and configured Mach3 to run on my computer.

For instructions and images showing the installation of the CNC Fusion X2 conversion kit, go to the CNC Mini Mill Conversion Kit (Hardware) page or go to the CNC section of Make Projects with more CNC related tutorials coming in the future.


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Comments

  1. Anonymous says:

    Great rundown, thanks for the details!

  2. Anonymous says:

    I converted my HiTorque Mini Mill to a CNC setup too this summer (I’m using EMC2). I still haven’t made the writeup, but I did just upload a video of it the other day:

    I ended up stuffing the computer and all of the electronics into a 26″ toolbox. It came out well as did this build. :)

    1. Anonymous says:

      Great video macpod! So cool, the red tool box is a great idea. 

      Your digital Arduino tachometer hack is on the top of my project lists for this week, can’t wait to get that installed. 
      http://macpod.net/misc/sx2_tachometer/sx2_tachometer.php

      1. Nick Raymond says:

        Hey MacPod, did you install limit switches?

        1. macpod says:

          Nope, I hven’t actually. I thought about it but I have found heading to the machine’s home before turning the machine off and homing the machine as soon as I turn it works perfectly fine for me. LinuxCNC also has an option to track the machine after the first home so it theoretically will always know where it’s at provided nobody manually tweaks the machine. I don’t really trust that so I’ve stuck with the former approach :)

  3. “The company started in 2004 when Michael Rodgers, a machinist by trade, wanted to create a CNC machine but realized that he could not build the parts he designed without first owning a CNC machine. ”
    Sounds like the CNC Mill version of RepRap. And you know the saying, “Once you build one, you will have the skills to build one.”

    1. Rahere says:

      At long last, someone using leadscrews! I think the jury is now back in
      with the results of trying to reinvent that particular wheel in the
      various RepRap designs, with the decision that these are essential: the
      play in the other designs makes 1:1 reproduction quality nigh on
      impossible in the long run, and they’re spending way more than they save in attempting to find a work-round..

  4. Pete MacMillin says:

    So how did it work? Since this was labeled a review, I really was hoping for some concrete information here. Was it worth it? How much did it cost? How does it perform? Speed? Precision?

    1. Anonymous says:

      Hey Pete, 

      More information on the way, at the moment I am still having difficulties with the IBM laptop running Mach3. In the process of scavenging an old desktop from a friend to use as a designated work station. Since the install I have used the Mach3 wizards to cut circular pockets and jog the axes using the DRO for reference while cutting steel and aluminium. 

      I also designed plans to build an enclosure for the CNC mill over the winter vacation, where I will be able to run the machine more frequently and for longer periods of use. Plenty of opportunity to test and collect data.

      1. Anonymous says:

        Laptops aren’t so great for cnc setups. To save power, the do other strange things that will make RTOSs hiccup. Before you totally ditch it however, try going into the bios and turning stuff off like ACPI if you can. If you get a dual-core machine, you should experiment with turning off one of the cores too (I did this and it had an effect on the max jitter I saw).

      2. Nick Raymond says:

        I have worked out most* of the kinks with the laptop and it seems to run ok. However, I would not recommend buying a laptop just to use for CNC, there are just to many issues with latency timing interference from Bios features as mentioned above. The plan is to upgrade to a cheap desktop in the summer and build a metal swing arm with the display and keyboard attached. Still running Mach3, I am getting use to the interface and am now looking into making my own custom screens but I would still like to get EMC2 up and running to really compare both programs.

    2. Nick Raymond says:

      Small update:

      The hardware from CNC Fusion runs about $700 if you purchase three optional Heli-Cal zero backlash couplings. There is also an additional $45 charge for the Little Machine Shop as they bed is longer and requires longer ball screws.The parts arrived very quickly. http://www.cncfusion.com/minimill1.html

      You can purchase the 3 motors, stepper motor boards and the breakout board from Probotix for $350. I chose to get the “Ready to Run” option so when the package arrived all I had to do was mount the motors and plug them in to the controller box. With the additional relay board for turning three 120v devices on/off the total price tag was closer to $625 and included all the wiring,fans, power chords and small stuff like fuses, nuts, bolts, and all the other small stuff you forget about until its time to actually assemble the kit. https://probotix.com/index.php?view=product&path=22&product_id=118

      I am very happy with both kits, the stepper motors are able to move the table and head of the mill easily with nice smooth motion. They have plenty of power for this size mill. After carefully adjusting the gibb screws and fine tuning the axes on the mill, I used a dial-indicator to measure the backlash in each axis at 0.003″ well within the range that CNC Fusion advertises. I have found that I need to adjust the gibbs screws every time I run the machine as the screws become lose due from the vibrations during cutting. I hope to remedy this by purchasing a large thick steel plate (1/2″-3/4″ thick) to anchor the base of the mill to the table and make it more rigid. I’d also like to fill the column with expoxy cement, I hear this really helps to make the mill more rigid and better at holding its tolerance. http://www.cnczone.com/forums/mechanical_calculations_engineering_design/63992-270_pages_e_g_anyone.html

      If were to do it again, I would not purchase the HiTorque Mini Mill with the solid column, which I suspect would be slightly more rigid than my tilting column mill. Even for manual milling, I would HIGHLY recommend the LMS mills for a home shop even if you have no intention of converting to cnc. http://littlemachineshop.com/products/product_view.php?ProductID=3960&category=1387807683

      Two buddies helped me build an enclosure for the mill using 3/4″ plywood to prevent the chips from flying all over the garage, so I hope to start shooting some videos once I get the mill installed and wired. More to come…

      http://www.flickr.com/photos/76583381@N07/6872859675/

      1. Stevyn says:

        Sorry, you would or would not recommend the solid column LMS X2?

        1. macpod says:

          I would suggest the solid column. I converted my tilting column to a solid column setup and noticed a difference. The metal is thicker which reduces chatter when cutting. If you need to do angled cuts, you should angle the piece if at all possible.

  5. Bill Griggs says:

    This is a great article. I am in the process of converting my Minimill to CNC using the Stirling Steel plans http://stirlingsteele.com. I plan to use leadscrews instead of Ball screws. I have a Shumatech D.R.O. (digital Read Out) that I also plan to add along with the CNC. I soldered up the board myself.

    I recently upgraded the Mill from gears to belt drive. I posted pictures and a description along with a couple of videos. http://www.makermasters.com/seig-minimill-x2-belt-dive-upgrade

    Really glad Make is  posting great articles like this. Great job.

    Bill

    1. Nick Raymond says:

      Bill, thanks for sharing the video. My X2 from LMS came with the belt drive installed, but I recently crashed the machine into a chunk of aluminum going WAY to fast for the bit that I was using. Now the bearings in the spindle whine around 1000 RPM so I will need to open it up eventually and fix/replace the parts. Feel much more comfortable after seeing your video.

  6. Brent Hannah says:

    I strongly recommend using EMC2 on a linux box. I am using for an NC mill that I built using plans from http://buildyourcnc.com.
    You can find EMC2 (for free) here http://www.linuxcnc.org/

  7. In every kind of market, Asset-trade offers used CNC equipments available at Asset-trade that are used to be able to enhance the excellent and performance of the different procedures. Used CNC equipments have been used by men to reduce their work. Even the easiest device which is the handle has been confirmed beneficial in a lot of programs. Actually this has even been the reasons for the more complicated devices and resources that sectors are experiencing these days.

  8. Dimitri says:

    what happened to the hardware link?

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