Picture of Building your own CNC router/milling machine

Already at the age of 12 I was dreaming of making a machine which could make things! A machine which would give me the opportunity to create products for in and around the house. Two years later I stumbled ont the words 'Computer Numerical Control' or more specifically the CNC milling machine. After I found out people were able to build one themselves in their own shed, I knew it! I had to build one, I yearned to have it!!
For three months I tried to find the proper parts (A dremeltool, drawer slides, pieces of wood, etc.), but I didn't really know how to build a CNC. The idea fell into oblivion.

In August 2013 the idea to build a CNC milling machine captivated me again. I just finished the first year of my bachelor in Industrial Design, so I was confident enough to start a build. The real difference between now and 5 years ago was, I learned to work with metal on manual milling machines and lathes and above all I had the right tools to design a machine.

This Instructable will show you how I built my CNC milling machine. I know a lot of CNC dreamers do not have the knowledge or tools to build a full metal machine. I still think and hope this Instructable inspires you to make your own machine. I include all of the necessary steps I went through in designing and building this CNC milling machine. All of the drawings I used to build my machine will be available.

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Step 1: The Design and CAD model

Picture of The Design and CAD model
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It all started with a proper design, in my case a few sketches to get a good feeling for the dimensions and shape. Quickly after the sketching phase came the CAD model. I created my model in SolidWorks. If you plan to design your own machine I recommend a parametric CAD-modeling tool. Your machine will most likely have a lot of parts which have to fit together neatly, sometimes with some strange dimensions (for example pre-ordered parts). After all the parts were modeled, technical drawings were made. I used these drawings to machine all of the custom parts on the manual lathe and milling machine.

Since I'm a lover of good designed tools, I tried to make maintenance and the possibility to adjust things on the machine as easy as possible. Bearings could have been integrated in the machine, but I chose to place them in separate bearing blocks (in case it needs to be replaced in the future). Keeping your machine clean is very important too, so guiderails are all accessible (in case of the x-axis by detaching some cover plates)

De drawing above gives an overview of the main mechanical parts I will cover in this Instructable. I will of course also cover the electrical part of the machine. A PDF with the main dimensions is also attached.

Step 2: The frame

Picture of The frame

The frame provides the machine a rigid basis, not only to place it in your workshop but also for working on. To the frame the gantry will be mounted on sliding rails and later on a work surface. It also houses the stepper motor and spindle for the x-axis. I constructed my frame from 2 Maytec 40x80mm profiles, 2 endplates (both 10 mm thick aluminium), 4 corner pieces and a square structural piece.
All of the profiles are sawed right-angled and afterward milled exactly square. With the corner pieces a heavy (well relatively lightweight; it's all aluminium) frame was bolted together. The square frame made from the smaller profiles were mounted with 4 milled blocks (aluminium) on the inside of the Maytec profiles.

Since the frame sits beneath the worksurface dust could fall down on the guiderails (you want to keep them clean, more about that in step 5). To prevent this, dust covers were made and mounted around the guiderails. A angular profile mounted with brass milled t-nuts onto the may tech frame and 2mm aluminium plates mounted in the milled pockets on the endplates.

On both endplates bearing blocks are mounted for the spindle. They were hand milled and lathed to the right tolerances. On the front endplate mounting slots for the stepper motor were milled

All of the dimensions are documented in the technical drawings below.

Step 3: The Gantry

The gantry is the bridge between the x-axis guiderails and supports your milling motor above the workpiece. The higher you make it, the thicker the workpiece can be. There is however a disadvantage of high gantries. They work as levers on the guiderails and on the other hand the side plates tend to bend more easily by making them longer.

Most of the work I planned to do with the CNC involved milling aluminium parts. An average vise for the machine would be 60 mm high. Since the thickest blocks of aluminium easily available for me would be 60 mm high as well, I chose to space between the work surface and the piece of metal, which could hit the workpiece first, to be 125 mm. This gave me a starting point for the side plates. Since I wanted the center of an end mill hovering over the center of the runnigblocks (from the machines side view), the side plates had to be placed at an angle. Solidworks helped me to convert all of the measurements into the final parts. Because of all the complex dimensions I decided to mill these parts on an industrial CNC mill, this also gave me the opportunity to round all of the corners (would have been very hard to mill on a manual mill).

The part which supports the y-axis guiderails is formed out of an 5mm thick U-profile. It is mounted between the side plate with the help of two simple mounting blocks. On the inside the U-profile houses the y-axis spindle. Which is again supported by the same bearing blocks used for the x-axis. They are mounted on the outside of the side plates.

Beneath the main frame a plate was mounted on the underside of the gantry's side plates, giving a mounting point for the x-axis spindle nut.

All of the dimensions are provided in the drawings below.

Step 4: Last movement

Picture of Last movement

The last movement is what I call the Stepermotorhousing for the z-axis (plus the z-axis itself of course). It is constructed out of a frontplate mounted on the y-axis linear guiderails, 2 reinforcement plates, a motor mount and a backplate. On the front plate 2 linear guiderails were mounted for the z-axis onto which the Mountingplate for the milling motor was placed with the runner blocks.

The motor mount has the bearing for the z-axis spindle fitted into it. So I didn't use a bearing block for this spindle and is only supported on the top. he lower end is floating behind the mounting plate for the milling motor. The spindle nut for the Z-axis was directly bolted on the mounting plate for the milling motor.
The backplate provides a spot for the y-axis spindle nut to be mounted; it is mounted on the inside.

All of the custom mechanics are now ready. The CNC is assembled with the guiderails, spindles and a lot of bolts ;-)
De drawings are again provided below.

Step 5: Guide rails

Picture of Guide rails

Since your endmills need to move in 3 directions, the machine guides them with its guide rails. The guide rails provides the machine its rigidity in all directions except the one it moves in. You want them to let the machine only move in the preferred direction. Any backlash in other directions results in inaccuracies in your workpieces.
On my machine I wanted to use guideways supported on the full length of the rail, reducing the risk for deflections on the longer axes.
In my opinion some kitchen drawer slides are preferred above the hardened steel rods which are supported on the end (yes! they will deflect). Since you are constantly fighting the forces from the endmills against the material of the workpiece, a lot of support is recommended.
I chose the most expensive option; profiled linear guide rails with runner blocks. The are designed to receive forces in all directions. In the third picture you can see the looping bearing balls, they are positioned on both sides of the profile. All with a tangent 45 degree relative to each other, giving it the ability to handle high loads.

To get all guiderails perpendicular and parallel to each other they were all aligned with a dial indicator (with a maximum difference of 0,01 mm). If you spent your time on this part, the machine will perform very well in accuracy!

Step 6: Spindles and pulleys

Picture of Spindles and pulleys

The spindles translate the rotational movement from the stepper motors into a linear movement. When building your machine, you can choose between three different version; leadscrews or ball screws, either in metric or Imperial configuration. The main difference between leadscrews and ball screws is the accuracy and friction. Leadscrews tend to have a lot more friction and are less precise than ball screws. If your looking for a very accurate machine without any backlash, you should definitely consider ball screws. However, they are relatively expensive!

I chose to use leadscrews with a special plastic drivenut which reduce friction and are approach a backlash free system. You can order the drive nuts here:\

Both the ends of the x- and y-axis have to be turned to size to fit the bearings, pulleys and clamping nuts. Since the z-axis spindle is only supported on one and with a bearing, it is turned on only one side.

The pulleys are drilled to the turned shaft size (in my case 8 mm) and provided with a M4 setscrew perpendicular to the shafthole.

The drawings below show the dimensions

Step 7: Worksurface

The work surface is the place you will clamp your pieces of material on. On a lot of professional machine a T-slotted bed is used, giving you the option the use T-nuts and bolts to clamp your materials or vices. I chose to use a square piece of 18 mm birch-plywood on which a screw the materials and replace it when needed. An affordable work surface! You could also use Mdf with anchor nuts and bolts. Try to avoid screws and nails in Mdf, it doesn't grip them as good as a plywood board.

The work surface could be milled flat by the machine itself after you've completed it. Your first project :-)

Step 8: Electrical system

Picture of Electrical system

The main components in the electrical system are:

-Stepper motors

-Stepper drivers

-Powersupply (or 2)



-And last but not least: Safety first; a emergency stop ;-)

I chose to buy a complete set on Ebay with 3 Nema 23 stepper motors, 3 suitable drivers, a breakout board and a 36 V power supply. I use a step down converter to convert the 36 volt DC into 5 Volt DC. You can of course also put together your own set. Since I could not wait to sartup the machine I temporarily mounted all the drivers and power supply on a open board. The enclosure is in the making.

Since a few years it is also possible to connect a CNC very easily via USB. The UBS-breakout boards on the market generally come with their own software. I chose to use the parallel printer port found on most older PC's. I do not intend to use a new computer in a room full of dust, oil and aluminium chips

Since I had a lot of difficulties in finding a proper scheme with the needed components, I tried to make everything clear in the infographic above (you can also download the PDF and zoom in on the different parts)

Step 9: The milling motor

Picture of The milling motor

Since we want to remove material from the piece we clamp to the work surface, we need something that drives the cutting bits; i.e. the endmills. The milling motor will spin the cutters at low or high speeds. From a simple Dremeltool to a High frequency Spindle of several kWatts. For our machine size a Kress spindle is very convenient to start with. If you want to improve your machine, a reliable Hf spindle will please you. It all depents on the amount of money you can afford to spent on it.

Try to find something with the ability to use different sized collets.

Step 10: CNC software

Picture of CNC software

In the topic CNC software I'll discuss not only the program me that controls the machine, but also the software which produces code the machine will understand.

When we make a workpiece on our computer, either flat or a 3D CAD (Computer Aided Design) model, we need to convert it into something the machine will understand. With CAM (Computer Aided Machining) we can read vectors and 3D models and create an output suitable (Gcode) for the software which controls the machine. I'm allowed to use the professional software offered by my University

The software that controls the machine is a Gcode interpreter. When you use a USB-hub, as discussed in Electrical system), it will have it's own software. If you use the parallel printer port on a older computer, you can choose your own. I chose to use Mach3 since it it used by most hobbyists. You can find a lot about it on forums and google. Since Mach3 has many options and functions, I won't explain them. Just play with it and you'll discover its secrets :-)

Step 11: It's Alive!!!

Picture of It's Alive!!!
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Ones connected properly, hookup the power supply, it just works!! Start with some pieces of wood or foam and you'll get used to the speeds and properties of your machine. The work above shows some of the pieces I'm working on in aluminium. As you can see the machine is able to work very intricately.

Search for proper parts and take your time. I could have build the machine in a month, but because I had to search for parts on Ebay etc., it took me half a year. This keeps the costs down of course, I was able to build the machine for less then €1000,-

I hope the story encourages you to build your own CNC milling machine. Please feel free to contact me or give a comment if you think something is missing.

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Is it possible to know the price of each piece alone

How much money would this cost to make?

How much money would this cost to make?

Do you have a YouTube video of this running?

th3-1nonly28 days ago

I will make this when the opportunity arises, however, the guide is really comprehensive and thought through. Thank you for the great information, I will post pictures when this project is done :)

Trochilidesign (author)  th3-1nonly28 days ago

Great, I'm looking forward to that!!

bubbo28 days ago

can i ask what is the thickness of the Gantry sideplates? Looks like 20mm thick aluminium?

Trochilidesign (author)  bubbo28 days ago

Indeed, they were milled out of 20mm thick aluminium

bubbo28 days ago

Hi Trochilidesign,

first of all, great design! I'm thinking of using your design to make my own, i was just wondering: do you think it's possible to use the same dimensions and make the working area bigger? Let's say 60cm x 60cm. Or would i have to change the structure?

Trochilidesign (author)  bubbo28 days ago


Of course you can, you just need to find the longer guiderails for the gantry and make the whole gantry and the frame wider. So, yes, you would have to change the structure

phippsy271 month ago

wow thats pretty cool. im just at where you were about 7 years ago, a dreamer. Its amazing to see how far you can come (encouraging actually).

Trochilidesign (author)  phippsy271 month ago
Cool, that's the goal :)
fabiort2 months ago

Awesome proyect I am really interested in built it, but I would like to request to you the cad files

Me too

Too bad bruh

chessuraya1 month ago

Hey are the cad files for the cnc mill open source? :(

This is an awesome build ! Great job dude ..

SASABRASIL1 month ago
(removed by author or community request)
Trochilidesign (author)  SASABRASIL1 month ago
Dear SasaBrasil,

What kind of a PDF do are you asking for? Could you be a little bit more specific.
parsing1 month ago

Great work!!!!!!! thanks

PiotrM1 month ago

Hi, your project is very interesting, I'm going to do cnc machine, but I'm wondering about several issues:

- the center of gravity axis-z is not raised too high above the y-axis (u-profiles)?
- drive nut Y-axis is mounted to the plate Z-axis backplate - it might be better to mount drive nut to the Z-axis guiderailplate (between guides the Y axis)?
I will be grateful for your answer.

Trochilidesign (author)  PiotrM1 month ago

"the center of gravity axis-z is not raised too high above the y-axis (u-profiles)?"

I don't really get what your are trying to ask.

"drive nut Y-axis is mounted to the plate Z-axis backplate - it might be better to mount drive nut to the Z-axis guiderailplate (between guides the Y axis)?"

It depends on what you want. I decided to 'hide' the drive nut in the U shaped profile. and mount it to the z-axis carriage (in this case its backplate)

hsa my2 months ago

Hi, I would like to build a router using microcontroller and RIP. I need help

Total price = ?

Trochilidesign (author)  miron.bogdan.792 months ago

As you can read in the last step: I was able to build the machine for less then €1000,-. In several other comments I mentioned I don't have the exact number :)

msh13533 months ago

bravo trochilidesign thats's greet and professional

pjethy3 months ago

'too good.I am new . want to make one . could u help . I have to choose a software first free available and then I could see if i able to use it then i will make or purchase a controller board . These are the main problems for me.

Thanks in advance

nygma20043 months ago

This is just amazing. I would love to build a router, but what I am lacking most is time (2 small kids). After all I would probably ask for the BOM. I assume you have it already as I have seen this being asked below. What I could not get from your post is the working area of your baby?

Trochilidesign (author)  nygma20043 months ago

Hi Nygma2004,

No I did not prepare a Bill of Materials. Simply because of th specific parts I used and I assumed that the people who are planning to build this machine will try to source their own parts (such as guiderails, aluminium profile and leadsrews)

But since more people asked for it, I'll try to make one in my spare time. (I'm currently quite busy with studying)

The working area of the machine approximately 450x800 mm

mrdiaz3 months ago

very good thank for sharing.

michaelgc3 months ago

Beautiful, I have been looking into getting one of these for my middle school stem class. Maybe we can build one... hmmmm.

Trochilidesign (author) 4 months ago

I would like to thank you all for the support! Trochili Design has won 2 prizes with this Instructable because of your vote!

A very Impressive Build, And thanks for all the PDF's They're very useful :)

Steve Lim4 months ago

This machine is just perfect!!! I am inspired and wanting to build one. It would be nice if you can send me all the details like websites to buy, BOM, more specific guidelines and information. Thanks in advance!

kSaletta5 months ago

Such an amazing job!! Best one ive seen someone make EVER!

oscar_ib5 months ago

just awesome! congrats!

bfranco5 months ago

This is a well engineered and executed should consider offering it as a could easily get a 1000 pre-orders to get the price down, eliminate the risk, and make a nice profit. If you decide to do so, please let me know.


Trochilidesign (author)  bfranco5 months ago

Hi Bfranco,

Thanks for your positive respons! I'm already exploring the possibilities in producing kits. Since I'm a full time student as well, it'll take a bit more time. If kits will be offered, I will of course let you know!

billbillt5 months ago

Very good.....

Dear: Trochilidesign

I really like the way you figured out how to make CNC drill move to carving position because I am thinking about building a 3d printer based off the designs of this designs. I just wish it had better software.

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