Getting my CNC to work

Hi, as I have written in the mail day thread, I got this nice CNC machine! It has motors, but not controller and no spindle. I have no clues about these machines, so I thought, maybe someone here might be able to point me in the right direction :slight_smile:

I already got some hints from @Sonosus, he suggested a Genmitsu motor as a spindle. @Jos asked if a dremmel could fit in the holder, but I don’t think so.
But before the spindle I want to get the thing itself moving. As options I found some arduino shields. It looks like the most used shield is the CNC shield v3.51 from protoneer. It needs some extra driver chips (stepsticks) which come with different power and features (microstepping, silent operation) for different prices. How does this compare to the RAMPS mentioned by @Sonosus ? Is the more expensive “silent step stick” for the protoneer worth it? Does it depend on the motors that I have?
Both things are GRBL compatible, so I can still choose what program to run on my laptop, right? (I only have linux, so my choices for that might be limited)

Here are some photos again, also from the motors. The third motor is somewhere inside, but I think it will be the same as for the vertical z-axis (the smaller 1.55A)

1 Like

First of all, welcome to the wonderful world of CNC - I love my CNC machines and they are super useful!

Second up, do you actually know who manufactured this particular machine? The easiest way to get it running would be to find the external controller designed for that particular machine (from the photos I can see a parrallel port on the back there so I would suggest that is where it plugs in). If you can find the right controller - that it was properly designed to use - then you’re golden.

You might also give some thought to why this thing was put in a skip in the first place, and consider replacements for the motors, as I would say one or more of those having an issue could have caused the original owner to chuck it - for instance are you sure the third motor is inside, given the positions of all the others, and the apparent hole on the side of the X axis bridge which would suggest that the motor should be on the outside in line with the ballscrew that runs through the middle of it. And lastly that spindle mount seems a little thin, make sure you measure it and make sure that any spindle you buy will actually fit, because you don’t want to have to go replacing that if you don’t have to.

Do you have any local speciallists for building your own CNC’s? I am not sure where you are based but in the UK we have who would be able to supply you with motors, drivers, controllers and power supplies - along with replacement parts for things like the big screws all the way up to full kits.


Hey, thank you for all that stuff! I think the machine is a custom built CNC, so no official controller. It was found in the bin of a science institute and has no labels or anything. My friend also tested the mechanic and the motors and they work, it has probably been replaced with a newer/better model. I also think that the third motor is there, because there are some cables going into it :wink: But I will open it soon and have a look. I think from the mechanics it only needs some grease :laughing:. For the spindle, yeah I need to have a look at that and see if there even is anything that matches or I need to make a new holder somehow. For specialists I have no idea, but I will check. I imagine that there is something, but I don’t know yet.

1 Like

Ah, so they probably built it in house for themselves then… In that case you should first choose what software you want to use - for instance if you’re going to go with something like Mach3 that requires a specific kind of controller. If you just want something that will work with free tools go with a GRBL controller board - you can get those cheap as chips from China - and then put it together with a trio of 2 Phase driver units - again these can be cheaply sourced from China/Aliexpress - and then your power supply will be decided by your choices. Just make sure to leave enough headroom to run all of your motors and the spindle at full power at the same time and still have some to spare. Also, I can’t recommend enough making sure that you have home switches installed on all three axis to make sure you don’t burn out your motors trying to push outside the workable area, or possibly worse jam the whole affair.

As far as spindles go, you’ll need to make sure that it’ll do what you need it to and that you will have enough power to run it. If your unit is custom you’re going to want to make sure that you don’t replace those clamps until you can custom machine your own replacements - that Z-Axis unit would be a pain to replace completely if it’s custom job - so try and find a suitable unit that will fit. If you’re only looking to machine thin aluminium sheets (for say custom module panels etc) then you should be good with a basic Genmitsu spindle (if they’ll fit - again, go measure your clamps) but they tend to come in standard sizings, so find the one the science institute used and go with that.

Once you have your spindle moving and spinning, you’ll want to make yourself a nice wooden wasteboard and clamp it to the metal bed (so you don’t try and mill the extruded aluminium) and see how accurate it is. If it’s all nice and tidy, you’ll be up and running! A nice enclosure for your newly built power/control/driver unit would be an ideal test project. Make sure to add an emergency cutoff switch to stop everything in case of disaster, and if you can with your chosen controller board you might want to make an external control unit so you don’t have to wire it up to a computer to move it about - it’s super handy when setting your home position. Same goes for a Z-Axis zero position probe.

If you find out what each of those pins on the parallel port is wired to, you can create a nice custom cable that will allow you to connect your custom controller setup to the back port without having to redo your internal wiring too, which would be a nice touch.

And one final piece of advice that I have from my own experience - milling bits cost from pennies to many pounds, and you get exactly what you pay for. Don’t skimp out on your bits.

1 Like

Do you have access to a 3d printer? If so, you could probably 3d print a custom mount for whatever spindle/tool you plan to use. This way the spindle possibilities are endless.
Ramps boards are simple but effective - they’re basically just an interface to wire up the Arduino to the stepper drivers. They are dirt cheap from eBay/AliExpress but the downside is that it’s quite easy to fry the Arduino - they don’t have much protection.
@JonGreen seems to know his stuff though when it comes to control boards - I’ll leave it to the expert :slight_smile:

1 Like

3D printed mounts are great if you’re only planning on milling wood or plastic, they also work a treat if you want to mount a laser etching unit on there (you won’t be able to get enough power to cut metal that way, but they are fantastic for removing paint from metal for panels). Not so great if you want to mount something meaty like a dewalt router or a super powerful spindle.

If I recall (it’s been a while) Ramps were designed for RepRap machines, which share a lot in common with CNC and can be used, but your going to have issues driving that big 2.4A motor from them. If you buy a half decent dedicated GRBL controller board you won’t need the interface for an arduino anyway, it’ll all be on the controller.


Have a look at the video’s by Nikodem Bartnik on youtube, they are bound to inspire you. He made a CNC machine based on a dremmel.


His projects are great, I bought one of his IndyMill plate sets and I am currently umming and ahhing over just how big a machine I want to build with them. I am thinking something in the region of 1.3-1.4m square so I can use it to just straight up cut Kosmo cases from big sheets of ply.


Oh I can help!

I build an ozznest CNC kit but build my own controller on the cheap.

The drv8825 “stepstick” driver ic in a grbl compatible board or shield will be your cheapest and least effort diy controller. They can supply ~2amps easily and with some heat sinks and a fan they are almost perfect match for the pictured stepper.

Edit: 24v for the stepper will be ok, but 36 or 48v (better double check that) will be better. Don’t worry about voltage stated on the steppers, the amperage is what matters, so read the poulu? Guide to calibrating the DRV8825’s!

As for mounts, I’ve successfully milled aluminium sheets with my half 3D printed one, just print with good infill and it’s sweet.
However if you measure the existing mount you might find a “drop in” replacement mount and spindle on eBay, AliExpress or Amazon.
I spent a bit extra to get a brushless one the controller is a bit finicky and I manually start it. The 500w dc ones are cheap and the only thing to watch is the runout on the er11 collets. I have 2 which are fine and one that’s slightly off measured with my “eyemometer” (one day I’ll buy a dial gauge, and I do recommend getting one!)

Bits can be brought cheap online, but a bunch of single flute HSS ones and don’t worry about snapping or killing them before investing in any expensive carbide or whatever. The “coated” ones from the usual suspects are ok too.

Don’t fuss about silent stepsticks, pointless upgrade when your spindle will be making waaay more noise cutting things!

Happy to try answering any particular questions you have.


Wow! Very nice and helpful responses!! The Nikodem Bartnik videos are really cool! If I ever consider to build a larger cnc, I might go for his design…

I think I am going with the cheapest and least effort route, that @JaggedNZ proposed!
Will I have issues with the 2.4A motor, if the DRV8825 can only supply 2A? Will it just move slower/with less torque or will something burn?

That’s what I suspected, thanks for making it really clear :slight_smile:

I think the mount is relatively large (need to measure), but the space around it looks a bit tiny. I will see, first I want to get the axis moving and maybe just attach a pen and paint a little xD

1 Like

The 2.5A rating is the rating you do not want to exceed (this is not the whole truth but it’s close enough approximation) but you also want to get close to this to get the most torque (turning power) from it.

The DRV8825’s can deliver 2.2A, but you would be safer aiming for 2A as a starting point, overloading them is non-fatal, but it will cause them to miss steps and you will likely think you have a mechanical issue…

These drivers are effective current limiters that’s why you are able to far exceed the rated voltage of the steppers.

Oh, Does this have a stepper on each side of the Y gantry? For a total of 4 steppers? If yes you will need 4 drivers!

1 Like


The board already arrived!! There is only a single motor per axis, I think. I will test this tonight!


I can not upload the grbl software to my arduino Uno. Something about being out of sync. I can upload other sketches though…
I think it is too old (rev 1) and needs a new bootloader. At least that is what I read somewhere. Now I need to see how I use a nano to update the bootloader on the uno. I think I even need to add a resistor to the uno, because it’s rev 1. if anyone knows more about this, please give me some hints :slight_smile:

Okai, I managed to upload it! It was indeed solved by updating the bootloader on the UNO. It took me a while, but I did it with the arduinoAsISP sketch via a Nano that I had lying around. :slight_smile: I am now using the optiboot bootloader and I am considering loading all my nanos with it, because it’s so much faster when uploading a sketch :slight_smile:
So, now I have grbl on the UNO and I used sourcerabbit as a quick test. I have only hooked up a single axis now. It works!! But it is very loud! and also if I click too often on the “X+”-Button, it screams and stops immediately. I think I should add some oil or something to the moving parts… Maybe I’m missing something else.

Have you adjusted the current trimmer on the driver chip? Might be set too high… or you might just be trying to move it faster than it can handle?

You might want to look into dry lube, my setup is belt driven so I can’t give much advice there.

1 Like

No, not yet adjusted anything. Need to look into that! I have trouble finding the dataset for the motors, I would like to know what voltage they like… so far I used 12V, maybe that’s too little?
Oh, and the screaming only Happens if I push the jogging button in quick succession. When I tell it to move further in a single command it seems fine… is that expected?

Yeah, I suspect you are pushing them too fast, that’s easy to do particularly if you have not calibrated step to mm/in or have current limit set too high or too low,

Do not worry about the voltage rating, it will be something stupidly low and almost as meaningless unless you are using old “dumb” stepper drivers. With current regulating drivers like the drv8825’s you want to give them as much voltage as you can manage (within what your drivers can handle) then regulate the amps/current supplied. That said you will likely be happy with 24v and lots of industrial power supplies are available at 24v.

Watch the temp of your steppers, if they are getting hot (like close to too hot to touch 50c+) then back the current limiting down. Heat is the main enemy as that can demagnetise your stepper cores.

I run at 24v (more like 27v really, I pushed the voltage reg as high as I dared) but I’d much prefer to run at 36v, I just haven’t had the time to upgrade.

1 Like

I have a 24V power supply now and I am using 8th steps now. Much smoother! :slight_smile: yesterday I started connecting the other axes as well, but the parallel/centronics connector drives me absolutely crazy :stuck_out_tongue_closed_eyes: Connections don’t make any sense! At least now I know that they come out different than how they get in. Need to measure all now. I hope I did not burn anything so far by making wrong connections!


After a long time I do now have all 3 motors working! I also got an old dremel from my brother! Let’s see what can be done with this!


sounds cool! I use the same controller for my millright cnc, recently built it a new enclosure: