[m1n1m]

As the topic says I want to build my first CNC mill but I'm not sure where to start this process. I've found this forum and a few other sources and read up a bit on the subject (still got lots more reading to do). From what I can figure out I think a mill would suit me best as I want to fabricate parts in alu/steel/stainless mostly for my car hobby but maybe also later at a professional level if I can get things working good and to cover some of the investment. I haven't done much machining before and the closest I get tho CNC milling would be my 3d printer at the moment. I know this is two different worlds but some of it is similar. I work with PLC systems (programming/debugging/testing) at work so I got some basic knowledge about electronics but very little in the mechanical department.

I looked at Grizzly G0704, Weiss wmd25v, Weiss wmd30v and Sieg X2 and some Chinese ones on Aliexpress but I can't figure out what I should go for. Shipping also seems to be a problem to Norway cause the shipping of the Grizzly from USA cost more than the machine itself.. The ideal situation would be to buy a Mill that is often rebuilt into a CNC mill so there are "kit" of the parts I need for the conversion as I don't have access to lathe/mill and would have to hire someone to do work like that before I get my CNC mill up and running. Is this possible?

Also what should I expect a project like this to cost? My original budget for this kind of project was $2000 (was then thinking router) but a friend I spoke with said that the last thing I wanted to do was to buy low quality/not rigid equipment when I wanted to be able to mill materials harder than steel. The reason I'm asking is that I could get a Optimum M2 cnc for $7000 and that is including a lot of equipment/cooling/lubrication/tools++ and it does look a lot better than the manual mills I mentioned above but it's also way above my original budget.. I'm kinda clueless on the second hand value of a machine like that as well so I'm going into this part blind but I'm feeling that I learn some while reading through whatever info I can find

[dharmic]

I'm in a similar position to you. 3D printer, have done a fair bit with part modelling and printing and kinda know my way around the basic G-codes and how it all hangs together, then went to a milling machine.

I already had an X2 mill but they're sloppy as hell and way too small for the things I wanted to do. Plus I'd hit issues with a CNC conversion on it years ago.

I bought a Chinese router instead, a slightly better quality one than the cheapies. And I'm glad I did. Because even though it has its limitations in terms of materials etc, it meant I had a working machine to start cutting stuff with straight away. Not just a project stretching out past the foreseeable future to get a mill actually running. My next machine will be a homebuild or a converted knee mill, but I'm super glad my first one was off the shelf and I'd recommend the same to anyone.

Onto the good bits: you can buy an Optimum M2 for $7k? My POS chinese router cost over $5k by the time I had it in an enclosure and plumbed up with coolant, tooling etc. And it's just a stepper driven router, not a proper servo driven metal eating machine. And it comes with tooling etc?

Check the travel distances against the things you want to make. If it fits, that Optimum is going to save you a whole stack of pain and time to get up and running and it will take care of you for a while. You might want to check it for slop, backlash, wear in the ways and so on but if each axis moves smoothly and without play and everything's in good working order? I'd be saying it's no decision at all. Find the cash. Because $7k for a proper metal CNC mill is cheap!

[sajurcaju]

Speaking to your car hobby al/fe/stainless, you might end up with a lot better machine if you buy a used manual mill. You could add cnc later.
People cut aluminum with a router, but that's about all, and it takes a good machine ($).

[m1n1m]

Onto the good bits: you can buy an Optimum M2 for $7k? My POS chinese router cost over $5k by the time I had it in an enclosure and plumbed up with coolant, tooling etc. And it's just a stepper driven router, not a proper servo driven metal eating machine. And it comes with tooling etc?

Check the travel distances against the things you want to make. If it fits, that Optimum is going to save you a whole stack of pain and time to get up and running and it will take care of you for a while. You might want to check it for slop, backlash, wear in the ways and so on but if each axis moves smoothly and without play and everything's in good working order? I'd be saying it's no decision at all. Find the cash. Because $7k for a proper metal CNC mill is cheap!

It is not a brand new Optimum M2 tho that's why the cost is as it is. The seller is the only owner and he bought it in 2010 and used it for approx 500hours. He also says that the machine can't make big cuts (1mm deep with 10mm mill he said whatever that means) and that it doesn't work good in steel. Is it operating error with to much feeding or is that the case with these small machines?

Speaking to your car hobby al/fe/stainless, you might end up with a lot better machine if you buy a used manual mill. You could add cnc later.
People cut aluminum with a router, but that's about all, and it takes a good machine ($).

ok. Is the convertion hard to do without having lather/mill to manufacture the needed parts?

[sajurcaju]

I think it is really important for you to get experience on a manual mill. Based on almost no info (I could be wrong), it sounds like you haven't done a lot of machining.

Only being able to cut 1mm deep with a 10mm diameter end mill is not very good, indicating either incorrect feed as you mention or machine rigidity problems, only one is easily fixable. On a good mill you should be able to take a 5mm deep cut with a 10mm end mill.

If you were to convert a manual mill to cnc, I will point out that you *would* have a mill to manufacture the needed parts. A lot of people have done the conversion, there should be a lot of posts and web pages on this. I've got a wood cnc router and manual machine tools, so I can't point you to good write-ups myself.

Steve

[m1n1m]

That is pretty accurate Steve I got no experience with a manuall mill. I've used mills for wood and lathe for wood a lot but never on metal. Another good thing with getting a manual mill is that I can do this in steps. A lot of my work I could do just as easy on a manual mill so then I could take the expenses in steps instead of all in one go.

I'm very open to suggestions on what mill to go for to not go down a path where no one has gone before.

[dharmic]

1mm cuts with a 10mm is pretty gutless, looking over the specs again the motor is pretty lightweight and I expect the ways etc would be of the same kind of strength. Sorry, I might have got excited early over the photos of a "metal ready" machine in their catalogue.

I've had a rebranded SIEG X2 for about 12 years. It's got a tiny work envelope, it's gutless, it's sloppy on the ways, there are tight spots and a tonne of backlash on all the lead screws, but it's sorta kinda got the job done for everything I've been game to throw at it. Fun times trying to do anything but straight single axis lines though I did try and set it up for CNC but it just didn't have the rigidity, the straightness or the smoothness to make it go nicely so I ended up converting it back to manual and still use it for quick drill or rough jobs and it's fine for that.

When it came time to CNC again, I didn't even consider the conversion of this mill. I would consider one of its big brothers as my 2nd CNC machine, perhaps a decent sized knee mill for example, at least then it's got the guts and weight to handle some harder materials. My point earlier though was buying a mill to convert for your first CNC machine just adds a tonne of hassles to an already steep learning curve, and it's worth considering buying a pre-made one to get some learning on.

[sajurcaju]

Dharmic, you do have a point with the added work of converting a manual machine. I came at that issue from the other side; I have hugely enjoyed building my wood router from scratch. Depends what gives you jollies.

M1n1m, I have no idea what sorts of used machines and prices there are in Norway. A knee mill is a good idea. I started with a Millrite, like a Bridgeport but 2/3 the size. I moved to a Bridgeport when I came across one at a great price. Here is a site that is very useful when looking at older machines:
Machine Tool Archive
There are a lot of other good pages on that site.

Steve

[m1n1m]

I can't find many used mills on the market so I have only been looking at new ones tbh and those are very expensive. I see that you suggest a router, dharmic but wouldn't that only be for wood/plastic/circuit boards and not the metal I want to machine?

[sajurcaju]

I noticed (never saw this before) that Tony has some used tools advertised. Again, I'm in the US and have no idea how involved shipping would be from the UK to Norway:
Machine Tools For Sale & Wanted
All I've done is make use of the reference page I mentioned earlier, no idea if his prices are good or machine condition, etc. There have to be used sources closer to home. Sometimes used equipment takes a lot of patience.

Steve

[m1n1m]

Thanks for the link. I'll do some more research here in Norway first as I suspect shipping from UK will be very expensive for 300kg+ machines like this.

I found a Jin Shin 3.7kW manual mill for sale not far from me. Will try to contact the seller and see what kind of offers he have gotten on it. It just says "bid" on price so it might be out of my range but will ask around some.


Anyways, been thinking about what dharmic said earlier and I could get a long way with a router also if it could do aluminum with good accuracy. The only thing is that if I invest $2-4k in such a machine those money is kinda blown if moving on to a proper mill later :S

[awerby]

If you can. find a CNC mill with a bad or obsolete controller to retrofit, rather than a manual mill. Believe it or not, these often go much cheaper, since they don't work, and shop owners will often sell them at scrap prices just to free up the space. A mill intended for CNC will already have ballscrews, so you won't have the difficulty and expense of replacing the leadscrews. And even if the servos don't work (often they will), at least you've got the bearings and mounts ready for the replacement. Usually they'll come with a spindle with a VFD that's controllable by software, rather than a manual push-button.

You're still looking at spending some money to put in a control system, but you'd be saving a lot versus starting with a manual machine. If there are some machine shops in your area, you might call and ask about any mills ready to retire. And if you want to be able to accomplish accurate and effective milling of aluminum, you're much better off with a mill than a router. Save your money, keep looking for the right machine, and be ready to move quickly once you've found it.

[m1n1m]

You mean something like this FINN – VTC 30 CNC fres - defekt! (norwegian text, but the pictures will tell some). It has a defect spindle and cost $1400. I guess the spindle can easy cost a load tho..

[dharmic]

Sorry M1n1m, I was relating my own experiences rather than making a recommendation in that post. For steel and TI a router probably won't do it. I don't consider it wasted money though. When the time comes (and it will), my router can be sold to recover a fair bit of that cash. Or I can keep it for timber and plastic work. Or I can strip it for parts for other projects.

I do like the idea of repairing a busted CNC but, as already mentioned, get one with the control busted rather than anything else because - as you've already guessed - things like spindle replacement cost an absolute bomb.

[awerby]

Yes, if it's the spindle itself that's broken, it might be too expensive to be worth fixing. But if it's just the VFD that powers it that's blown, you should be able to replace it. Keep looking; and check out the machines you find carefully; don't be in too big a hurry to spend your money, and the right machine will find you...

[m1n1m]

Will do. I keep seeing cheap big machines like Eumach mc800p that go for just over 2k but I guess it's harder to get rid of those than the small machines I'm looking at.

If I where to not mill anything harder than aluminum would a router do the job then or will it be very slow in alu? I notice that there is compromises in both ends here with low rpm on mills making them not so good for circuit boards/acrylic/wood and the other way around with routers lacking rigidity for harder metals

[dharmic]

You'll find my OMIOCnc thread kicking around, essentially I bought that unit because it had decent linear rails, ball screws, a control box that worked and a decent torquey 2.2kW spindle.

I use it on aluminium occasionally, and it works. But the spindle is not the right one for the job. Aluminium surface rates on HSS tooling mean RPMs are down well below where the torque really is and, by all accounts, I'm going to have this spindle die young if I keep pushing the bearings etc at low (2000-4000) RPMs for the design. And the little steppers are not going to smash through high feed rates, I get about 200mm/min on aluminium and that's about it at the moment.

So it'll do for occasional ali, but it's not optimal. I'm still glad I got it because it gives me somewhere to learn and it still does the job. Next time round I'll have a benchmark against which to rate options, too, which (like you) I really didn't have coming in.

[m1n1m]

Today I've been looking some into routers and the main focus has been rigidity. This is the only one I've found with 4x20mm guides on the Y axis and it also has 20mm guides on X and 16mm on Z. It looks pretty rigid also. Could this one setup with a 2.2kW spindle and VFD handle some light aluminum work? Should I look for something else?

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[dharmic]

I've not actually used them before, but I've read enough warnings about curtain rod style rails that I simply don't trust them to be rigid under ali loads.

[m1n1m]

could you elaborate? When you say "curtain rod style" do you mean the way the rods are fixed to the chassis? It sure didn't look clean but I figured that the Y axis is prolly the axis with most problems with rigidity and this had double the amount of guides in that direction to compensate for that.