We’re building a MPCNC! You can find the parts I used listed below, as well as the build videos and livestreams. As the build goes on, this page will get updated!
For the project I printed the official parts from V1 Engineering, but I’ve since learned that there are substitute community versions available that make metric hardware much more usable. After having built with the official parts, I can highly recommend not using them and printing the modified versions instead. (August 2019)
If you don’t have access to a 3D printer, you can also order the parts through V1 Engineering or services like 3D Hubs. But it’s more fun to print them yourself!
|Duet 2 WiFi||Mainboard||1||Duet3d||Matterhackers|
|MKS Gen 1.4 (set with A4988)||Mainboard (alternative)||1||Aliexpress|
|Coupler 5x8mm||Leadscrew coupler||1||Amazon||Aliexpress|
|GT2-2M 16T pulley||Belt pulley (5mm bore)||2||Amazon||Aliexpress|
|GT2-2M 6mm belt||XY belt (sets with pulleys available)||5m||Amazon||Aliexpress|
|Longer wiring set (optional)||Motor wire (etc) extension. Match to motor and board connector.||1||Aliexpress (motor cables)|
Aliexpress (generic 3DP wiring sets)
|Power supply||Electronics / steppersupply (24V 2A preferred, 12V 5A also works)||1||Amazon||Aliexpress|
|400W / 500W Brushless spindle set||Milling motor with speed control & power supply||1||Aliexpress|
|608 bearings (608-2RS recommended)||Used as linear bearings.||53 (often sold as 10- or 12-packs)||Amazon||Aliexpress|
|25x2mm tubing||Frame, linear rails||Use the calculator||Amazon|
|3/4″ GRT conduit tubing||US alternative tubing||Local|
Screws and fasteners (list at V1 engineering) are available through sources like Amazon, but I’ve found it’s much easier to find a specialized store that carries everything in a consistent quality.
Alright, I got this MPCNC built, it moves, it cuts, you were able to follow the entire build process live here on YouTube. Last week, I was out filming a few project and when I got back, I wanted to actually tune this thing in and get it to cut well. Because what we were seeing on the last livestream was that there was an enormous amount of chatter and just bouncyness in the toolhead, especially in the aluminum cut, but also already in MDF, I know even from flimsier machines, that shouldn’t be that way, but somehow, this machine was just not rigid enough to mill into the material. And yeah, I did build this one slightly larger than they normally are, but what I was noticing was that the belt and the way the belt was mounted introduced a lot of flex into the drive system. Like, I could easily stretch the entire belt assembly by a millimeter or two, even with the zip tie as tight tight as possible. Now, in the comments, you guys have already suggest a bunch of different areas where my machine could also have issues, like these long M8 bolts that are used in the carriage having a smooth shaft instead of being threaded all the way through, which could have the carriage flex more than usual, but I wanted to go step by step, fix the obvious issues with my machine first and try and understand the MPCNC a bit more during all that. And I thought it would a good start and an easy fix for the belt with a new printed part that would directly clamp the belt with no zip ties. But it wasn’t that easy.
While I was already drawing a new part, I wanted to go ahead and work on a few other challenges that I ran into during the build, like the fact that there are only a handful size options available for tubing, none of which are really as cheaply available here as metal conduit is in the US, the fact that almost none of the nut traps were grabbing the lock nuts properly and I’d had to jam a screwdriver in there to hold them, and a few of the parts only seem to be made for imperial-sized hardware from the start, not metric.
So I started in Fusion 360, created a new parametric design and drew up the first part, one of these corner pieces with adjustable wall thickness, screw size, rod diameter, and, of course, it has the belt just pushed in sideways with no zip ties or anything. Worked great, so I tweeted about it, was like, hey I created this part, if anyone wants to use it, here’s the Fusion360 design, I’m sharing this as Creative Commons 0 aka public domain, print it, modify it, include it in your project, you don’t even have to give credit for it, basically, do whatever you want with it. And here’s where it got complicated. Because Ryan of V1 Engineering, he designed the the original MPCNC parts, came in and was like, “Hey Tom, you can’t actually release these parts as public domain, they’re a derivative work of my original parts, so you need to release them as Creative Commons Attribution Non-commercial.”
Now, just to be clear, I didn’t just import the original stls into Fusion, chop off the zip tie brace and add the belt slot, this part is designed from the ground up. I spent a couple hours on the design to work out kinks with being able to adjust the dimensions as parameters without the whole design falling apart, and yeah, it does look like the original because it fits the other original parts and, honestly, there just aren’t a whole lot of other options to design a part that does the job of holding a belt right there and clamping down onto a section of tubing at the same time. We’ll actually come back to that later.
So what followed on Twitter was two days of discussion between Ryan and me of what is a derivative design and what is not, who holds copyright to what and what the morally right thing to do was.
Now, obviously, I don’t think this part counts as a derivative design from the original MPCNC, but what Ryan kept pointing out is that he basically considers any part a derivative of the original as long as it fits onto the other parts because the dimensions and positions of features are the same as the original.
So I was like, ok, if you’re saying that any part that does the same job is a derivative, and that would require me to only release my design as Creative Commons Attribution Non-commercial, too, then so be it. But then please do respect that license and don’t use my original work commercially, either, including in derivatives. Now if we follow that line of thought, Ryan owns the copyright to this area, I own the copyright to that, and in the end, nobody gets to use it. I thought holding up a mirror would show how ridiculous this entire thing would be, but instead Ryan accused me of wanting to destroy his MPCNC project. Like, what?
So, just to be clear, I started out by wanted to release my design with no restrictions for everyone to use, for the MPCNC community and for whoever wants to make the part, there’s also an awesome community supporting this channel, so whenever I spend my time and design something, I want it to be available for as many people as possible. And for me, that means releasing as open-source. A non-commercial license isn’t considered open-source because it comes with so many restrictions in how you can use a design, for example for educational use, in a makerspace that, yes, usually has member fees, or in any other context where someone is making money with it. For example, me even building the MPCNC on this channel is a pretty grey area because I am “using” the parts in videos and livestreams that, at the end of the day, put food on my table. Thankfully, I do have implicit permission in that case.
I have no intention of harming any project that enables people to do awesome things, in fact, I want the MPCNC to be as awesome as possible, which is why I started making modified parts in first place. But it looks like, for the time being, the MPCNC is going to be Ryan’s project alone, with him wanting control over the entire thing. And he obviously made it pretty clear that he didn’t want me “interfering” with that by making open-source, compatible parts.
Now, there is still that little detail in copyright where if a part only has a certain shape, because it has to do a certain job, copyright just doesn’t apply to it. That’s why, for example, your car’s brake discs aren’t protected by copyright from Ford or someone, because the shape they have is not “design” in the artsy way, it’s purely function, and copyright only applies to “art” and creative work in the widest sense.
I’m pretty sure that, aside from the MPCNC logo on here, these parts are very much only functional, too, so copyright really wouldn’t hold up. I’m certain that all things considered, I did nothing wrong, but I’m going to respect the fact that Ryan doesn’t want this.
So that’s what I’m going to do, unfortunately, this means I won’t be spending any more time on this MPCNC, the only thing left to do is to take this machine apart. I’m sure I’ll find a new home for the spindle, electronics and all that. Again, my intent was to make the machine better, more flexible, more accessible and of course I don’t care if this belt clip thing makes it into the official design or even ends up being sold as the MPCNC. I mean, after all, this design was CC-0 to start. And that even includes use in projects with a restrictive license, too.