Here is a way to make a computer controlled milling machine. That puts the real power of a computer control machining into the hands of the average human. Small enough to set on the desk but scalable to any size. As inexpensive as possible without sacraficing accuracy (too much). All most all the parts can be purchased in local retail stores. And above all CHEAP you can be up and running for well under $200. With it you can do 2 Dimentional engraving and PC board etching and 3D milling and modeling in Foam, Wood, Plastic and other soft materials.
Also try watching the YouTube movie at the end (the last frame).

New information on the Motor Driver Circuit is (HERE).

Step 1: The Frame

The frame needs to be a flat base that you can mount everything on horizontally and a goose neck of some kind to hold the Z axis (the up and down part with the motor tool)firmly in place. I used one inch pipe just for fun but as it turned out it was pretty handy too. When I needed to make adjustments I could just tap it with a hammer. As you can see the post that holds the Z axis doesn't have to be in the center. It just needs to be firm and the water pipe does a good job of that. Later, after you are sure all the pipe joints are in the right place, you can add a drop of thread sealer to the joints and it will be a good solid structure.

Step 2: The X Stage Rails and Motor

Next its time to add the rails for the X axis stage. These rails are 3/4 inch U chanel aluminum that you can get from the hardware store. Put a washer under each end to space the rail off the pipe just a bit. Don't worry about the rails being perfectly parallel. You'll see why later. Now mount the stepper motor with a bracket like you see here. Connect a length of 1/4 by 20 threaded rod to the motor shaft with a short piece of rubber hose (1/4 inch fuel line). Now your ready to set the movable part of the X axis(the stage).

Step 3: X it Stage right

Take a piece of plastic(I used Plexiglas) or metal, something strong and flat and mount a piece of the U channel to it. Now the tricky part. The round thing is a bearing. You can get them out of motors or buy them at a hardware store. Mount it to a short piece of aluminum like so. Then take a 1/4 in. coupling nut(a long nut) and wrap it with aluminum like so(see pic.) The bearing will hold the X stage to the X rail and the coupling nut will allow the motor to run the satge back and forth. It wouldn't hurt to grease the skids a little and the nut too.
Here's a video on making the bearing fixture.

Step 4: The Y stage

The Y stage is just like the X stage but turned 90 degrees. Mount two rails and a motor on the X Stage and then take another piece of flat material and a U channel and make the moving Y stage. Make the little bearing thing and a coupling nut for it too. When your done it should look like this.

Step 5: Zee Z Axis

Again we are going to reproduce the X and Y Stage to create the Z axis stage. Take a flat piece, here I used a piece of white Plexiglas. Mount some rails and a Motor to it. Then make a moving stage piece with a u channel and a roller bearing. We'll do something a little different with the nut(see picture). The four posts you see on the stage will hold the motor tool. Now since this stage is going to move up and down the weight of the motor tool will make it want to come off of the rails so lets add a few more roller bearings to each side to keep it together.

Step 6: Get it together

Now we slap the motor tool into the Z stage. Then its time to mount the stage to the frame. And there you have it. This is the mechanical structure. From here we will need to hook up the stepper motors to a controller and get some software running on the computer but I'm going to save that for future articals.

Step 7: What's it Do

If you were interested in this project it's likely you have already seen what can be done with an 3 axis(XYZ) computer controlled milling machine. What is suprising is what kind of accuracy you can get out of this thing after you tinker with it a little bit. Make sure all the rails are held firm and straight. Tighten the roller bearings so the stage doesn't shift.
I used it to make PC boards. It's real good for engraving name tags and signs. And it's pretty exciting to see it carve a 3D object out of a block of foam or plastic.
WARNING there's a lot to learn about the software. Some venders offer package deals of motors, drivers, and software. That makes it easier but you pay for it.
I'll add more to this later. Send me comments and questions.

Step 8: Easy Mill the movie

If the literal instructions are confusing try watching the YouTube movie:

Also check out the follow up instructions on Stepper Motor Control: Easy Mill Stepper Motor Controller

Step 9: Engraving

Now that I got the machine back together after making the instructable and I did some engraving and made a PC board.
Cutting plastic is no problem but doing the PC board the bit went a little too deep on the left side of the board and took out all the finer traces. This is when you start tweeking on it. Just take some aluminum foil and put it under the rail of the Y axis. So as the stage travels left to right the height of the bit should stay the same.
Notice I'm just holding the material down with masking tape. What I like about this thing is, it's easy to fix these kinds of problems because it's all made from simple elements.
Here's the new video:

Also check out the follow up instructions on Stepper Motor Control: Easy Mill Stepper Motor Controller
Hey Tom, great project! I had a lot of fun building this and as soon as I can scavange a DB25 cable, i will be able to use it. Here are some of my pictures. The table is 9"x11". I added a simple fish tank pump to blow off the dust. The plexiglass extenders allow the router to utilize the full 9" x11". I will be posting pictures of my slightly modified circuit board.
<p>Hello I am a beginner, if you can be with you help I have stuck to trapezoidal Data do not know. Thank you.</p>
<p>sir,will you please tell me the diameter of x-y axis shift and what is the size of thread on that shaft for e.g(1 mm, 2 mm or 5 mm)...please</p>
Considering you've finished yours, do you think that a machine with 10" x travel would have to have 20" x rails, or is my logic screwed up? Thanks, snow
Wouldn't the extenders flex and cause the table to move? Either up/down flex due to the weight of the Stepper, or torsional flex as the motor moves the table?
the weight of the table itself, the anchoring provided by the x axis motor provide stability and prevent wobbling of it.
fish tank pump- sweet.
&nbsp;<span>This is my version of Tom's CNC. It uses the stepper motor 3 Axis CNC Driver Kit from chromationsystems.com (Jeff from Chromation Systems was a ton of help and his instructable is here: <a href="http://www.instructables.com/id/Parallel-Port-3-Axis-CNC-Driver-Opto-Isolated/" rel="nofollow">http://www.instructables.com/id/Parallel-Port-3-Axis-CNC-Driver-Opto-Isolated/</a>) and I am using KCAM for the software. I named my machine CNCme.</span> You can also watch the Youtube at: <a href="http://www.youtube.com/watch?v=Uzli11WJeo4" rel="nofollow">http://www.youtube.com/watch?v=Uzli11WJeo4</a>.&nbsp; Thanks Tom, Jeff and Instructables.&nbsp; <br /> <br />
Nice Carabac!&nbsp; Where did you get the slides that you used?
The slides are off a network hardware cabinet.&nbsp; I purchased them from a local surplus store.&nbsp; They are very nice because they run on ball bearings.
&nbsp;Hello<br /> <br /> I make this CNC Milling Machine<br /> <br /> Thanks Tom &amp; Instructables<br />
Wow! Great work!<br /> <br /> Does that panel behind the machine related to it or is it something else?<br />
Thanks&nbsp;<br /> <br /> yes panel is related to&nbsp;machine. all the kit and wiring inside of panel.<br />
That looks like an excellent version of this instructable!&nbsp; Is there a possibility of you doing an instructable of your panel?&nbsp; Looks great!<br />
Here is my mill I guess its not cnc and does not follow many of your design concepts but you inspired it!
that's rad. it's like an etch-a-sketch mill!
hi tom, i too was inspired by your simple design, and actually guided a high school project based on your designe, the hope was that it will enable students to make low cost pcb in school. after the project(wich was a bit diffrent from yours and didnt works all that well duo to my lack of technical skills and experience(im 18) and other things) ended i decided to make a V2 wich is almost the same as yours, and it dose work well,i manged to see it do very presice things with a pencil. the problem is i cant find a right drill for making the pcb's,(im pretty sure thats it) i got this 8 pcs kit from drill bit city but the drill that dose the routing dose not have a pointed tip in the very end and there for dosn't penetrate the circuit until much pressure is applied but then it goes in way to deep, im guessing its the drill bit but id like to hear what you say, and maybe recommend me a drill or a set from drill bit city or anywhere else(take in account i live in Israel ) my main goal is PCB's although i already did some name engraving and it came out very well! 1 more thing... is there a way to use lazycam with kcam? and what do u think about mach3 it look way more complicated is it any better?
Wow! I like the design of the machine in the last three pictures... Do you have any kind of build log for it? More pictures? What did you make the frame out of? Thanks, snow
hi, yes sure there are plenty more pictures at my website (sefi.tk) the frame is made from U channels alone, it was a much much more stable design yet it requires precision with assembly cutting and the whole process, out of my experience, after building 3 models, its clear to me that the cost of a stable machine is it requires more precision in ever step of the way, if you have experience, tools, and two right hands then go for something stable, otherwise stick with the basic plans. btw i solved the whole pcb making thing by getting an endmill and made already a bunch of pcb's and many other thing, thanks alot tom. hopfully my next project will be my own instruct-able :P
Regular Dremel engraving cutter (#105) works fine for me. It's 0.8mm wide and I use it for PCB Isolation Routing. You can find it in any hardware store (Ace\Home-Center\Rosenfeld) here in Israel.
i tryed ace/homecenter with no luck, in tel aviv & hertzliya where exacly did you get it? by the way lior, i sew you website - VERY NICE :) i want to talk with you if i could il email you from your forum.
Congratulations. That's a good piece of work for a class project. I can give you some tips on PCB work. The motor tool can have a problem with wobbling, that is the bit may be off center. It may have an aluminum collet that is just not very good. I was suprised to find the 3 jaw chuck replacement worked better. May be because it has more mass. Also I found bits at this site:<br/><a rel="nofollow" href="http://www.precisebits.com/products/carbidebits/scoreengrave.asp">http://www.precisebits.com/products/carbidebits/scoreengrave.asp</a><br/>Good job. <br/>I hope this works for you.<br/>Tom<br/>
Hi Tom your design is fantastic and so easy to make this is now the second one I`ve made, I work in a uPVC window factory and so I made mine out of welded uPVC window frame. I got my stepper motors out of an old fruit machine of all places! Still needs a bit of tweaking but I`ve routed a few PCB`s and everything works great. Rob
Last night I completed my construction :D Tom, Thanks so much for helping me get here! Here's some pics (yeah I've still gotta hook everything together)
This is my first full-on, serious project I have done from this site. Well, maybe I shouldn't say that, as i am not quite done. Went shopping for most of the supllies this morning, which took me from Home Depot to Ace Hardware to Big Joe's. The only things I need now are the plexi planes and the motors, which are coming. An interesting day to say the least. Also, I don't suggest getting the pipe at Home Depot, as they semm to be downgrading their one-inch pipe supply. Weird. Here are the pics so far, how does it look? You can see the threaded rods in the back.
I have also started one of these projects and have completed two stages. I also made some changes to the design perhaps you may find them helpful. The upper image is the current state of the project. If you look on the upper rail, I have added limit switches to prevent over travel. I found the switches in various microwaves which I salvaged for parts. The second image shows the roller tensioner. I uses two roller blade bearings and some picture hangers with springs, purchased at the local hardware store. Added a couple bends to the hangers, so the screw head would not rub on any surfaces, then located a pivot point which would allow the rollers to contact the guide and allow the sprint to tension. see third image. The last image shows how I added connected the threaded rod to the bracket. I found these screws used to go into the bottom of wood legs, drilled holes to match the prongs and bent them over to fasten the item to the bracket. The coupling was created using a few collars and a nylon bearing. I also used 8-32 threaded rod which I need to add shrink tubbing to in order to mount it in the coupling. Hope this helps
Nice use with the u-channels on mounting the motors. I really like that idea, and i might steal it from you, haha. But it is looking great, you are quite a bit farther than I am. Still waiting on those motors. Lol.
Also, the spring tension on the bearings is an interesting concept. Perhaps i'll try that out as well. The amazing thing about this project is it's versatility to make changes.
Well the inspiration comes from your genus. I truly like this project, I agree with your former comments. I have used a very stiff spring, as for the rails,and I have made plans to expand the length, but for now I just wanted to prove out the design. Glad you told me about lubing the rails.
Quick question, I am looking for some cheap steppers, and ebay definitley isnt the place. Any ideas people? And please dont jsut say "copy machine", i mean where would you find a copy machine to destroy?
You can find copiers at a electrically resycling senter. I just hacked on apart to get the two steppers out. Althou i dont know if both are steppers (hmm i can really feel the steps so i guessing it is.)
Try MPJA.com here's <a rel="nofollow" href="http://www.mpja.com/products.asp?dept=101">The_Motor_Page</a><br/>Pretty good motors for around 10 bucks<br/>
I was looking at this web site and I need some help on figuring out what motors to buy. There are a couple of different degree per step and a bunch of voltages and currents/resistance of coils. Which ones do I get??? I've never dealt with steppers before. Help!!
I did a bit more digging and I came up with something I felt might work so I ordered a bunch to play with. They are from www.allelectronics.com, part number SMT-89. Its a Oriental Motor Vexta, PX245-02B-C8 which is listed as having a 1.8 degree step. Its 6volt, .8amp 2 phase. If the picture is correct it looks like it has a collar with set screws to attact to the drive bar. It has 6 leads and is currently at 5 bucks a piece. I bit the bullet and ordered 6 so I'd have enough to build two machines. Sure hope these will work, I'd hate to waste 30 bucks but I decided to take a chance.
I think your going to be very happy with those. I like the brass shaft couplers on them. Five bucks is a really good deal.
I thought so too. I got 6 of them, I figure I can build your design as is then use it to help make the next version. My original, and on going, reason for building this is I want to use it to help make pinewood derby cars. I'd like teach my kids some 3d design and let them play with creating car shapes in software then have the CNC machine mill out the basic shape which they can hand finish. With your current design what is the envelope? It looks like its somewhere around 6 or 7 inches and I need at least 8 and 9 would be best so I figured instead of offsetting the z axis I'd use the longer piece of pipe on each side to get a slightly bigger envelope.
Got the motors yesterday. They do come with the brass couplers. I'm planning a more direct method to connect the all thread to the motors, I bought 5/16 instead of 1/4 inch thread and am going to mount it in my lathe and cut off about 1 inch of threads and size it to fit the coupler, looks to be about 3/16. I'm planning on doing the same to the other end but fit that to a bearing that I can mount to the frame. Harder to get everything alligned but should make for a much sturdier setup.
You can return anything you buy from them within 30 days. Just follow instructions on yellow sheet. No return nubers needed just what you are returning and do you want a refund or credit. It's that simple.
That looks nice. Looks like you used cutting boards. The thicker the harder the flatter the better. A word of caution and not to discourage you especially because this design technique allows you to easily make changes. The bearing may need to be pressed very firmly to the rail so that the stage won't shift when milling. The spring may work but you should make sure it's very strong. I also suggest just one bearing in the center will allow the stage to travel 1/2 way to the left and 1/2 way to the right. It's also good to have the rails extend well beyond the travel of the stage. Aside from that Id like to say an awsome job and to all of you undertaking this project far out, right on - ride on.
Oh yes...and don't forget to grease the rails. That aluminum will grind into powder.
Hey nice job. That looks like it will work (so far). Keep us posted. People will want to know how it goes for you.
Quick question. What type of bit did you use for drilling into the steel? I had quite a bit of trouble with my current bits. Threading it was a breeze though.
I found that a sharp bit works the best (just Kidding). I just used a regular high speed steel bit. It's hard but after you get the X Asis rails and motor set you don't have to drill steel any more.
Well that's good. I guess I'll try a higher speed on the press. Oh by the way, what kind of motors did you use? They look like Vexta, but i'm not sure. I am about to order some Superiors myself, don't know how well they will mount to the frame though. Guess I'll find out.
I got two of the motors out of an old coppier and one out of a floppy drive. They all worked at different voltages but all I had to do is change the light bulb to get the torq that I wanted. Slightly larger motors wouldn't hurt, The smaller ones tend to get a little hot. As long as you've got more than 4 wires comming out of it you can be 99% sure it will work with the circuit.
Well I am using a pre-made driver board, and the motors are 60oz, so ill be able to use them later hopefully.
I just won the auction on some stepper motors on ebay and am looking in more detail at building this. I just wanted to ask you to please explain the roller bearings in more detail, like what kind you used and how you secured them to aluminum you used. Thanks --Josh
OK here I just posted a youtube video on how to make a bearing fixture. Enjoy<br/><div style="margin-left:15px;"> <object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/Y6vDllrRSDw"></param><param name="wmode" value="transparent"></param><embed src="http://www.youtube.com/v/Y6vDllrRSDw" type="application/x-shockwave-flash" width="425" height="344" wmode="transparent"></embed></object></div><br/>
Awesome! Thanks a lot for posting extra videos to give us a better idea how some of the parts were done. Question -- Where did you get the tiny bearings? I'm having an awful time trying to find a source for bearings. Thanks in advanced, and thanks a lot for keeping up with us.

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