Easy to Build Desk Top 3 Axis CNC Milling Machine

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.

Comments

[userhck]

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.

[Tom McWire]

Hey nice job. That looks like it will work (so far). Keep us posted. People will want to know how it goes for you.

[userhck]

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.

[Tom McWire]

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.

[userhck]

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.

[Tom McWire]

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.

[userhck]

Well I am using a pre-made driver board, and the motors are 60oz, so ill be able to use them later hopefully.

[fredan]

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

[userhck]

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.

[userhck]

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.

[Tom McWire]

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.

[Tom McWire]

Oh yes...and don't forget to grease the rails. That aluminum will grind into powder.

[fredan]

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.

[userhck]

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?

[Tom McWire]

Try MPJA.com here's The_Motor_Page
Pretty good motors for around 10 bucks

[userhck]

Thanks!

[wpflum]

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!!

[wpflum]

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.

[Tom McWire]

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.

[wpflum]

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.

[hexapod]

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.

[wpflum]

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.

[gus_452000]

Some photos of the build so far, everything is going very well and I am very pleased with it so far. Hope that Tom can still recognise his design but here in UK very limited to what I can get hold of, hopefully the bits for the interface will arrive and I can build that and see if it all works :o)) The mini tool I found in a second hand shop for £3.00 about $6.oo and works very well up to 25,000RPM and 145watts so we shall see. Keep building and posting, you started something very good here Tom. Will post again when the interface is built and I have some photos of the fist mill. regards Gus

[Tom McWire]

Hey Gus looking good. That's the first Z axis I've seen. I think everybody gets a little stuck there. Now for the motor drivers and you'll be up and running.

[codex]

Hi, I loved your frame design! Can you please post the height, length and width of it? Thanks

[gus_452000]

Hi, the back piece is 14" long the legs are both 9" long and the neck is 9" long all working except for the Z-axis due to a faulty counter chip (replacement on its way, Mine is almost finished and as you build you notice the weight going up and up, its now very heavy. Thanks to Tom's great design been using the machine to draw pictures and lifting lowering the Z-axis by hand, great fun. regards Gus

[gus_452000]

In case you need to know the X-axis on mine are 19 1/2" and the Y-axis is 11 1/2" the neck is 4" away from the end of the frame, try and get it a little closer to the end is you can it will give you a slightly larger cutting area. regards Gus

[fjr122]

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

[Tom McWire]

I just discovered a really good source for bearings. Just go to your local skate board or roller blade shop. Or try this http://www.skatebearings.com/
Then just take a flat head screw with a head that's a little larger than the hole inside the bearing. Screw the bearing to a small piece of aluminum.
I'll try to put up a video of it soon.

[fjr122]

I've been looking at bearings for months.

The least expensive I've found is definitely http://www.vxb.com .
They have many many sizes and more than a few that are less than $1/bearing.

The last time I built something with bearings the best way I could figure to get a solid structure was to use some 8mm shoulder bolts from mcmaster.com (about $3 each) and some 8mm washers ($0.79 each). So I'm really wondering how you got your bearings good and steady without using shoulder bolts or expensive washers.

[Tom McWire]

OK here I just posted a youtube video on how to make a bearing fixture. Enjoy

[fjr122]

Cool, I will start building mine soon. :)

[akiriwas]

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.

[akiriwas]

Scratch my question -- I should have read more comments. Thanks everyone.

[la3bna]

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.)

[fjr122]

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)

[sefi]

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?

[Tom McWire]

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:
http://www.precisebits.com/products/carbidebits/scoreengrave.asp
Good job.
I hope this works for you.
Tom

[codex]

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.

[Roidy]

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