CNC Milling Machine

Would love to see some pics!

Has anyone seen a successful homemade automatic tool changer around the interwebs?

Try this link. Crappy video but it’s the best I could do while videoing with one hand.

Air operated 4x4x1 cylinder. Actuated with a 24vdc air solenoid. Could be operated through gcode if the right control setup is implemented.

I have seen ATC’s in action on similar machines. The controls and gcode requirements are beyond my current knowledge set. I actually have the ATC built for another machine but my lack of knowledge and limitations of my controls stopped the project. The control limitations have recently been upgraded by the manufacturer so I may revisit this project.

That’s great!!

Definitely on my list of most-wanted upgrades.

@TCandee Yah I havn’t seen it in action until now! That looks great!

@Cdavis You can actually purchase entire ATC carousels for TTS tooling on Aliexpress/Alibaba. I had a link to one that I was looking at, but its broken… I looked around for a couple of minutes and I couldn’t find it again. But I swear they are out there.

Here is some information on the LinuxCNC forum to setting up an ATC:

Tormach probably shut it down. They are pretty diligent about their patents and copyrights infringements. Thanks for the link but I am using Centroid Acorn controls.

The power drawbar is a fairly simple in theory. I bought plans from (or something like that) a long time ago and modified it for this mill. It is fairly expensive and requires a lathe for the “top hat” the attaches to the spindle. Drilling 6 blind holes in the top of the spindle is also required. As well as anew drawbar.

Air solenoid $85
Air cylinder $580 Fabco Air MP4X1/2X4X1FF-AS

Air cylinder is capable of 2800# force at 60PSI

I used 16 tormach Belleville washers in this format (())(())(())(()).

I used this same setup on a smaller mill with an air cylinder that had half the power an I used half of the Belleville washers. I seemed to always be right on the edge of having enough holding power for heavy milling so I doubled up on this one. The holding power is easily decreased on the washers and air cylinder by adjusting air pressure and backing off on the drawbar.

I’m not brave enough to commit to anything with “Linux” in the title :stuck_out_tongue:

I bought a MASSO controller. I’ll share my experience with it on here when it’s all up and running.

Do you remember what you used for pulse-per-revolution on the drivers?

1500??? I’ll fire it up later and check. The higher the number, the more micro stepping and lower holding torque. Also, depends on what steppers you have too. I haven’t even cut anything with mine yet. I committed to not milking
anything else until I have an enclosure. all parts are on order. Tired of the chips all over and getting tracked into the house as well.

Todd Candee

Oh, nice! Would really like to see your enclosure project.

I’m on a farm in Missouri and mine is currently in a 40x60 shop. I’m going to let the chips fly over the summer but it gets NASTY here in the winter. Think 33-degree mud soup. Shop doesn’t have HVAC so it’ll be migrating into my attached garage when things start getting messy. An enclosure would be the bees knees.

Thanks for the 1500 number. Now I have a place to start.

My apologies you did not say you use Mach3/4. I got confused from watching so many DYI videos on plasma CNC.

What operating system do you feel will work better for me between OpenBuilds motion control system or Linuxcnc since I have no IT experience with programing. No doubt both systems are great!!


You can’t really compare these two programs. OpenBuilds CONTROL is really just a G-code sender with some bells and whistles. LinuxCNC is very different. You should read through the LinuxCNC website and wiki (

Have you ever operated a CNC machine before (3D Printer, CNC router, etc.)?

Hi David,

Thanks so much for sharing this project! I was trying to settle on a CNC mill project and was looking at the PM 833 or 940. You really helped me make up my mind. I have been a Linux geek since the dark ages, so I definitely admire your choice of software!

I just wanted to ask before I get started if there is anything significant you would do differently now that you have had had a couple months with it?




So far there is nothing that I would have changed about the build. I have had some people be like, “Oooh you should have went with a double ball nut on the screw” or “you should have used epoxy for tramming the base.” But so far the mill has worked for what I have need it to (e.g. adaptor and mounting plates).

My one regret is the drewtronics probe. I don’t want to throw too much shade because the idea of a low cost probe is great. But this probe is just not reliable. Sometimes it triggers sometimes it doesn’t. I have pulled it apart a couple of times to see if the contacts are oxidizing, but nothing stands out. I am trying to find a new probe for <$1000 because the Probe basic GUI is awesome.

Edit: Best of luck on your conversion. Please share pictures and updates!

Pulled the trigger on my mill last weekend. I intend on following your walkthrough and plans to the letter minus the tool setter and probe. Might need some help along the way!

So did you ever wire the vfd to work through the mesa board? I’d like to go that route from the get go. Thought I’d ask here first.


Hey man! I apologize for not responding to your first post, but I am definitely excited to see how your conversion turns out.

I have not wired the VFD to the mesa board. I will need to add a pneumatic draw bar before I do that. You have to have the spindle on to counteract the force of the wrench when loosening or tightening the drawbar, and it would be too much of a hassle to turn it on through the software each time. You already need three hands to insert a collet/tool.

However, I will hopefully have a video coming out by the end of the year of some big upgrades to the mill. Stay tuned and let me know how your conversion goes.

I’ll posts some pictures later. I’m working on the enclosure right now while I wait on the rest of the electronics to come in. Did you put just one fan on the electrical cabinet for cooling and where is that wired into. Sorry I’m green when it comes to electrical. I’m gonna have to delve into the cnczone to figure out the VFD wiring through the board. I’ve printed of the other diagrams from your site that that other user uploaded but I’m lost in the sauce when it comes to that.

Pictures would be great!

There are two fans in a push/pull configuration to bring in the cold air and exhaust the hot air.

The fans are plugged directly into the tri-power supply (12V). They turn on whenever the box has power.

Let me know if you start to really struggle with the VFD. I can zoom you and can try and help sort you out, but it may be the blind leading the blind scenario.

Dr. D,

A few years back I built a 4ft x 5ft CNC router from scratch and after trying some aluminum a few times, I’ve decided to build one specific for metal work with a bench top mill as the base. Should be fairly easy/“cheap” as I will use the same electronics from the cnc and swap back and forth using quick disconnect connectors. I plan on continuing to use the router specifically for wood and plastics.

My question is your choice of the 833. I’m flip flopping between the 833TV and the 728VT. I know the 833 is much more machine for not that much more money but I’m a bit afraid of the size difference. Thoughts?

Love your videos by the way and will be using it for my assembly in the near future!



Hey Craig,

This is a difficult decision. There are pro and cons for both. With milling machines weight is everything. Larger castings allow for a more rigid setup, which decreases tool chatter (deeper cuts can be taken and better surface finish can be achieved). The Pm-833TV is twice the weight:

Pm-833TV - 750 lbs

728VT - 370 lbs

However, it’s important for you to ask yourself what are you going to be using this CNC mill for? Is this a hobby where you want to learn how to machine and program? Or will you be using this for small production runs? Is there a certain size part that you have to make?

If this is just a hobby and you are new to the game, then I recommend the smaller machine -728VT. Two burly men could probably pick it up, making it much easier to disassemble and work with. Also, its 30% cheaper. That’s nothing to scoff at. At least in my area, hobby level CNC mills have great resell value, so if you need a bigger machine then you can sell it and upgrade. However, many people go from hobby level mills to a haas (or comparable brand) because they want more sophisticated features like ATC, through spindle coolant, chip augurs, etc.

If you have some experience with milling, a lot of time to kill, or the need for higher quality and deeper cuts, then go with the bigger machine!

Let me know if you have any more questions!