Dave's 24" x 24" Build

Hi Makers,

I’m just starting to build a 2’x2’ MPCnC. I’ve been toying with the idea of building a CnC for a while. I saw this on the Hackaday blog, and it’s just what I have been looking for. The bundle kit is great, and saves me a bunch of time figuring out what I need, and ordering parts from all over the world. I have a PrintrBot Simple, a bunch of filament and a hardware store close by. I couldn’t resist the Buy Now button. My kit is on the way!

I plan to use this mostly for small projects, plastics, plexi-glass, PCB’s, and aluminum things. I’m going small. If I want big, like I decide to carve out a new front door, I can buy more EMT. Once I get this up and running, I would like to try some vinyl cutting, and maybe some laser burning. Maybe screw on a print head if I need to make something bigger than my little printer can handle.

First decision is what color will I use. I have a big roll of blue and roll of white on hand. Looks like it will be blue and white. I started printing a few days ago, and I have a Rigid Coupler, 4 Corner Blocks, one Roller F, and another Roller F in the printer. I checked the sizes of all the parts, and they all can printed on my 100 mm cubed PrintrBot except for the new Rigid Z. I could print the old one, but I’m going to try a cut version. I cut it in the center, and I have two printed pins that will go inside the cut. I will glue these together. If it works, I will share what I have. Outside of that, the rest will be stock.

I’m trying to determine the build area size. I found a few hints, it will be about 13 inches square, and that will be good. So I could get a better understanding of how this all goes together, I put together a virtual model in D123 and I colored the parts to match my plan. This is a big help understanding how it goes together before I start building.

I can also see the legs need to attach to a table to make this rigid. I want this small so I can move it from the basement shop to the garage. I live in Wisconsin, and I have an unheated garage. It’s too cold to do much work out there this time of year except for emergency repairs to the snowmobiles! I like the design of the one in the assembly instructions. I think I will do something similar except without legs. I want to keep the CnC legs short, and if I need more depth, the spoil board could be removed and lowered.

I will post up pictures and updates as I go. Any suggestions are welcome!


File to big, here is a smaller version.

Awesome! Welcome.

Looks like you have read through the site and took in most of the information even though its scattered all over the site. On thingiverse geodave has made a build calculator it should answer anyquestions you might have on build/cut sizes.

Keep us updated, hooefully I shipped your kit already, I took the day off, so if i didn’t it will be on its way monday morning.


Awesome! Welcome.

Looks like you have read through the site and took in most of the information even though its scattered all over the site. On thingiverse geodave has made a build calculator it should answer anyquestions you might have on build/cut sizes.

Keep us updated, hooefully I shipped your kit already, I took the day off, so if i didn’t it will be on its way monday morning.



Thanks, I have been poking around here and Thingiverse, lots of good information! I had a bunch of questions, but found answers to everything.

I have a lot to do before I need anything in the box, so I’m not in the rush :slight_smile: Great web site and nice collection of things in the shop.


My Corner Blocks and Roller Fs are finished. They all came out good. I have test fitted the corner blocks on the conduit and they fit. It’s a tight fit. The EMT is lightly sanded and I used steel wool to smooth the surface of the EMT

I have been keeping my printer running, and I rarely do print times this long. After the first print of the Corner Blocks, I noticed the extruder stepper was getting very hot. My extruder/hot end is attached directly to the stepper on my printer and it the extruder has no cooling. I hung a small 40mm fan on the motor and this keeps it nice an cool. It also helps keep the filament cool as it runs through the extruder. Last night after running back to back prints, my other steppers were getting hot, I found another 12V fan and attached it to a battery pack. I put this in the back of the printer and this seems to help.

Today I printed the first Middle Z. I had to cut the part so it fits on my printer. After it was cut, I could fit both parts in the print space and do a complete Middle Z in one print. The attached picture shows the cut with the two pins inserted into one side. I also included close ups of it assembled. I will wait to glue them when I get the second one done.


Your steppers can get warm to the touch no problem. Most are spec’d to almost 100C continuous. On all my printers I have had to adjust the driver voltage, they are all over the place. If you think they are too hot just turn down the drivers a bit.

Those pins make me nervous, not for strength but for accuracy. If you find you z is a little skewed just use the MPCNC to print new ones when it’s done. Then replace them.

Pretty cool though, progress is always good. I still get excited when I build a new one so hopefully it’s a little like that for you.

What I did in D123 is first make the cut, I positioned the pins inside the part, then subtracted the pins. The pins should align the two halves if the cut surfaces printed perfectly. I sanded the sides on a flat board to remove any high spots and the halves mate up tight. I just need to make sure it mates up good when I glue them. I will also need to measure it up good once I get the Z axis mocked up.

There is a Hacker Space in town I have always wanted to check out. I think they have a printer :slight_smile:

Thanks for our input, that really helps!


My parts bundle came yesterday!! I used up all but a few coils of blue filament so I finished printing blue for now. I should have more blue filament by the end of the week to finish up the blue parts. The white Corner Block Locks are done, and the Roller Locks are printing.

While waiting on prints to finish, I organized my parts and did a quick inventory. I soldered up the resistor to a piece of 0.1in female header ( https://www.adafruit.com/products/598 )to make a socket so the resistor can be removed. I also tested the RAMPS/Mega board by connecting 3 stepper motors and connecting the power supply. I used Repetier to move the motors. I had some problems, but got it to work with another Mega I had on hand. I put a post in the Trouble Shooting section on this.

I test fit the motors on the mounts, and test fit all the screws and bolts. Some I had to run a drill bit through so the bolt slid cleanly into the hole. The holes for the solder-less wire connectors need to be tight so the screw will thread into the plastic. An 1/8 inch bit seemed to be the right size, so I drilled these and started all the screws.

I’m very impressed with the design of all the parts. I can see the detail put into these parts to make them printer friendly and strong. Well done!


So organized…or was that just for the pictures (thats what I do)? Hahah. I we get you up and running soon.

Organized Chaos, the parts table is organized, the rest is Chaos! :slight_smile:

Most of my major parts are printed. I have been test fitting all the parts as I go. Some holes needed a drill bit run through them. Most of the nut pockets were too tight so I used an xacto knife to take off the edge, and a small flat hobby file to remove anything inside the pocket. All of the bearing slots that had plastic on both sides I needed to file a bit to get the bearing to slide in.

The roller locks took the most work. There is no way the tubes would slide in these. I found a plumbing tool that was just a bit smaller diameter than the OD of the conduit. I wrapped sand paper around the tool, then sanded out the inside of just the roller lock until the conduit would fit and the mounting screws would start into the nuts.

I loosely assembled the corner blocks and roller assembly. I lightly sanded and finished the rails with steel wool, so they are all smooth. I put together the frame with rollers and test fit the gantry rails, everything seems nice and tight, and rolls smooth.

As my Z axis parts are finished, I started test fitting the Z axis parts. I’m feeling good about the cut Middle Z part. I have not glued this yet because I want to make sure the joint didn’t cause a misalignment. I think is looking good. I was mostly concerned the joint would have made the part a bit longer, but I’m sure it is very close.

I want to print my tool holder so I need a tool. Harbor Freight has a sale on there ¼” Trim Router, so I picked up one of these. I found a holder for this on Thingiverse. I did a little modification to it to reduce some plastic. The nut traps are a bit to large for my printer, so I had to shorten these a bit. The holes in the conduit are drilled and nut traps test fitted. I should be able to put together the z axis soon.

I’m enjoying the build. The printed parts are well designed, and the kit has all the parts to put it together.


Very nice, I am a couple of days behind you in your build. 10 minutes till the Z nut locks finish then I can finish the middle section. After that I finish the Z section. This is my first cnc build. I have owned my Printrbot Simple Metal for about a year now. I have mainly been using google sketchup to make my own little parts to help me with everyday life. I came across mpcnc by accident on thingsverse, I printed a corner block as a test to see how accurate my printer was and it fit perfectly. Two days later I had ordered the parts bundle and had quite a few parts printed. I didn’t put much thought into a color scheme so I kept on printing with what I had on hand, glow in the dark pla. Kind of strange but it seems very strong. My plans are also to build 24 x24 machine. I look forward to following your progress.


Very cool, you should post some pictures, I would like to see how yours is looking! Maybe a lights out shot :slight_smile:

I have had my printer for about a year. I make a lot of mechanical things that need to fit together. I have always been impressed how accurate you can make parts. But I always need to do some kind of post printing adjustments, like drilling out holes to size, filing inner surfaces, etc. I can appreciate the nice job Ryan did designing these parts that are printed on all different printers and different brands of filaments. I didn’t find a lot build posts with little issues people had and how they did it, so I thought I would include some build notes in my post.

I have been using D123 for design. Its by Autodesk and free for personal use. It isn’t overly complicated to use, and has all the tools to make things to scale.

I hope to have my Z axis put together this afternoon before the Superbowl, while I’m at this I will print out my legs. Good luck on your build!


At 2:00 am I came to the realization that I printed the ie version of Better Middle Z. It all went together but was too large. Oh well, start again when my new filament arrives.

Ouch, I printed an extra motor mount. I lost count and just kept making parts. This put me short on blue filament. I had an order into Amazon 2nd day air delivery for Hatchbox Filament. It took them 4 days to put 4 rolls into a box and ship it. They did make up for it by sending it overnight :slight_smile:

WOW! That’s exactly what I said when I put together the Middle Assembly. Putting that together had to be the coolest part of the build. Then I started seeing all the mistakes I made (attached picture called OPPS). I forgot two bearings, and the bolts are all backwards in the the Middle Z. Well, it was so fun, I did it again. I took the Middle Assembly apart, fixed the problems and put it together again (attached Picture WOW). Attention to the assembly detail is important. With the bolts put in backwards, I would have had alignment problems when I put in the lead screw. It was helpful to build the model in 3D first so I had a better understanding of how this all fits together.

I couldn’t resist to put it all together, so I call this my test fit. The movement seems smooth and tight.

I’m printing the legs now. I will work on mounting the stepper motors and wiring. After that I will put it on a good flat level base board and start squaring it up.

Getting closer. The legs are on, I screwed and hot glued them. I had a lot of sanding and filing to get the conduits into the printed leg parts. I’m noticing a big difference in filaments. Some filaments take less post printing work than others.

The frame is squared up, and I’m printing my tool holder. I have a small tool holder on now for testing. Next I will work on the wiring. I’m not going to use the solder-less connections. I made up some connectors and will post more on this later. I’m also going to ground all the metal parts. The air is dry here in the winter and electrostatic shocks are common. Electronics hate to be zapped with a few thousand volts.


It lives! Here is a Pen Plot:

Nice! Sounds like it actually went pretty smooth for you. The video is with the 2 part rigid z, still? If so that is some good work on that.