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Former MechE for a decade and I owned personal CNC routers and on my 6th 3D printer. The biggest issue with CNC is the cost for consumables and accessories. Need a special bit? $$$ Need stock to cut? $$$ Want a nice ER11 or R2 collet set? $$$. A nice vise? $$$ Cut something wrong with a carbide bit? Shrapnel explosion. 3D printing has a bunch of limitations but is a way better machine for hobbyist. But I have been eyeing the Millennium Machines Milo. A very fair price point for a traditional style CNC. You can also decorate it however you want with your 3D printer.

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It is definitely more expensive than 3d printing in terms of consumables but china/aliexpress has really good hobby-quality equipment now - if you don't mind the country of origin. Many of their coated end-mills are decent and < $5 depending on diameter.

Maybe not stuff you would want to run professionally but it works quite well in a hobbyist setting and a mistake won't cost you $50.

I also looked into the Millenium Milo, only downside for me and kinda why I decided to design my own Voron V0-ish sized mini CNC machine was the really large footprint for about 3x the work volume (work _area_ is ~2x afair). An enclosed Milo would take up about the same volume as two 350mm Voron's side-by-side. So footprint of a small desk.

Imo besides the price, the other big factor is just how much less forgiving CNC machining is than 3d printing - so many mistakes you can make, zeroing the WCS, wrong WCS, mounting the work different than you had it in CAM, ... bam, at least the work is ruined. That's kind of another longer-term goal with my CNC machine, reducing some of these errors if possible with a web-based UI and maybe some computer vision. But that's far off, I'm currently playing with using a camera for work-probing/WCS-zeroing and it's sloooow progress :')

Have you seen the Carvera Air? Not gonna lie, I'm equally tempted but that price point is tough to swallow. Its about $7-800 more than the Milo but has a bunch of things built in that you would probably would enjoy like touch probe leveling and camera zeroing. Its the "Bambulab" of the CNC world.

I designed a little machine that's smaller than the Carvera with a 300W spindle at a lower price-point but requiring DIY (my build is probably around $550-600 now), I kept it smaller for a couple of reasons but stiffness was one of them.

The Carvera has an excellent work-volume to machine size ratio. Afaict it's not the stiffest machine but quite decent. The spindle power looks about right for it's level of stiffness judging by the YT videos I've seen.

Like many things it’ll depend on your use case. Carvera Air is 200W vs Milo 1.5kW which could make a big difference.

Yeah, the 1.5kW spindle + VFD sounds absolutely amazing. It would be pretty nice to be able to cut some steel but not sure if the structure is stiff enough for it

There seems to be an upgrade path for cutting steel with a slower spindle and extra steel plates for added stiffness. There are other DIY CNCs that are designed for steel and use concrete for stiffness which are probably more appropriate - but they do cost more so it really depends on your needs.

What I think will really change things are the 3-in-1 fiber laser sources that can be used for welding, cutting, and cleaning. Building a CNC gantry that can use the cutter means large pieces can be cut from stock plate, assembled like a 3D puzzle, and very quickly welded together. While much more expensive than a Milo it is be a totally different category for capability. Plus a handheld laser welding, cutting, cleaning are very useful tools in their own right. I think laser welding is soaking up most of the supply at the moment but I also think it's just a matter of time before people figure out how to hook up the cutter to a CNC gantry like many already do with hand held plasma torches.

I have the Carvera (not Air) and it's a very good machine mechanically, the software leaves a lot to be desired.

It isn't even close to being the Bambu Lab of the CNC world, unfortunately, but I'd say only because of the software. If they open-source their controller, things might improve quickly.

Oh bummed to hear that, how’s the ATC? The ATC was always the most fascinating part for me for the original Carvera. The Air does not have this feature but it’s expected given the price difference.

The ATC works really well, better than I expected. Although without software support it is pretty much useless — I have no idea how people can recommend that I renumber my tools to 1-6 in Fusion CAM for every job.

What I did was write a post-post-processor of sorts that takes the .nc output, watches for tool changes, and using the tool library information automatically assigns ATC slots, renumbers tools, and generates pauses if collet changes are required (e.g. changing from a 6mm shank to 4mm or to 3.175mm).

That means I can now look at a list of assigned ATC slots, put in the correct tools, and let the machine rip, only pausing for collet changes. Pretty nice and how it should be.

However, I have to say, while the ATC is nice to have, I would not consider it to be the primary factor when buying a CNC machine. Those tool changes don't take long and are not difficult to do manually. It's much more important to get a rigid machine with limited backlash.

Kinda crazy, I know post processors cost money for CAM software like masterCAM but didn’t expect you needed to write one for a hobby CNC too. I know fusion360 had a post processing functionality but I think they moved that into the paid version. I miss the fusion360 of 5 years ago.

I think the Fusion posts are still available in the free version - afaik certain things like overriding the feed speed no longer work though.

And I only briefly looked into it, but most Fusion post-processors are just Javascript! (or at least based on it)

I wrote "post-post-processor". My code comes after the Fusion post-processor.

I'd just like to point out how stereotypical of a modern mechanical engineer it is to want to print everything out of plastic and not appreciate the greater versatility of a CNC router.

I can't count the number of times I've converted gasketed joints into O-ringed joints, slotted holes, casting lines and welds I've smoothed out. Yes, there are better machines for performing these tasks in metal but I can just tell the CNC router to go nice and slow and come back hours later. In addition to that there's all buffing and polishing operations you can do with abrasives and the ability to cut cheap wood templates and test parts. The 3d printer can make complex things relatively quickly and easily but it can't work with existing things.

I think it really depends. 3D printing allows you to be CAD lazy. Things don’t need to make sense as long as the interface is correct. You can also print another part if you mess up. You need to spend some time to make sure CNC parts are engineering sound. But most “experienced” and respectable engineers know their way around the shop. I have zero issues using a manual/CNC mill, grinders, brakes, or drill press. I did it all the time when the schedule is tight, my electrical engineer counter parts would order some off the shelf parts and I’ll modify it for the projects needs.

Any time I see a guide like this, everyone will go on and on about the types of cutters, toolpaths, speeds & feeds, etc. but will always gloss over work holding. For every action, there is an equal and opposite reaction. Without reaction forces, the best cutter in the world is useless. A sizeable chunk of your tooling will just be clamps and indexing tools needed to align and secure the thing you're CNCing, while also trying to keep them out of the work area. 80% of the end mills I've ever broken have been by crashing them into a clamp or vice by accident. This is another thing you tend not to see in 3D printing or laser cutting, or plasma cutting for that matter.

I didn’t know soft jaws were a thing until I started working. Even in college, they just teach you to hold the part up with spacer plates and crank the vise. One of the vendors I worked with was explaining why 4-5 pieces cost the same as 1 piece. The time and effort to make multiple jaws for each operation is the time consuming and expensive part.

There are entire books on workholding:

https://www.goodreads.com/book/show/53168863-jigs-and-fixtur...

https://www.goodreads.com/book/show/5042096-jig-and-fixture-...

I've switched from clamps to painters-tape-and-superglue and it's been great. Only for holding, not for indexing.

There's a much higher barrier to entry with CNC. I have a cheapo CNC - few hundred dollars - and really have only ever made one practical usable "thing" on it.

It's so slow and needs much trial and error to get a decent cut, I feel a more expensive machine would be much more versatile but cost 10x for the machine and consumables as you say.

With the similarly priced 3d printer I feel like I've actually saved a lot of money and hassle printing things. I can quickly download a model and print a perfectly useable "thing" in no time, often with no mistakes. Prusa slicer and a larger $5 nozzle has made things even better, even though I have an off brand 6 year old printer.

Lots of hobbies can get expensive though, especially when high quality tools are involved. I'd actually argue 3d printing is an exception to that.

Decent power tools and consumables rack up and don't even look at the price of hand tools from the likes of Lie Nielsen.

A reasonable quality plasma-cutter CNC table offers the speed and low operational cost most fabricators can manage well.

Having a CNC Router table in a non-industrial zoned area will not work for most people. Services like sendcutsend.com makes life so much easier... =3

I was in charge of one of these when I was way younger and they are awesome. Downside is that I don't want to house Argon and they're such a pain to maintain. Getting parts ordered is definitely magnitudes more efficient and significantly cheaper nowadays. You can get really nicely machined and anodized parts from China for the same cost as custom part shipping cost here in the states, it's crazy.

Budget 3D metal printers will eventually enter the hobby market, but I only get to work on my hobby on Saturdays. =3

where do ypu order your parts?

Probably alluding to JLPCB, but I have used xometry.com on occasion. =3

I use mine in my (finished) basement, or if cutting tropical hardwoods out on my back deck (I have a machine on a wheeled cart).

The noise from having a router and vacuum dust-collection running all the time can become a problem in residential areas. Most would like a full-sized machine that could directly handle standard sheets of material, but the space is not the only limiting factor (i.e. the insurance provider could pull something nasty with your mortgage creditors etc.)

Peoples situations will differ, and definitely check out reverse-spiral flute carbide-cutters if you handle a lot of sheet-work on a 2.5D setup =3

While everyone wants a machine for full-sheets of plywood, they're expensive, and not used for many projects --- a smaller machine suits most needs and there is always tiling.

My machine is quieter than my neighbor's drum kit --- and I've run mine after 11PM and you can't hear it over traffic and the nearby speedway (on race night) outside in the yard (a quiet vacuum helps a lot), but I have gone over to their house at 11:01 PM to remind them of what time it is.

>Having a CNC Router table in a non-industrial zoned area will not work for most people.

Lolwut? Throw it inside where the narcs can't see it (you'll want it inside or at least in an out building anyway). They're not loud. The venting you'll want isn't loud either.

Source: I do this stuff in my house.

Are you using a full sized "router" on steel plate, or a mini-engraver made from a hobby-motor on balsa? Even a compressor fed Plasma-cutter rig is usually far quieter by comparison, as cheap import engravers often just make a mess of the surfaces.

Best of luck, =3

My router itself is a 2x2 with the Vevor 3hp spindle (not a repurposed handheld wood router). The router, regardless of material it's being used on, is quieter than just about any woodworking tool with a circular blade. When it's indoors nobody cares. I mostly use mine for making wood mockups of parts before I make them in steel. I have more traditional tools for steel fabrication. The router makes basically no noise compared to the "loud" ones of those.

The Millennium Machines Milo does look interesting. I wish there was an inexpensive cast iron or epoxy granite equivalent to aluminum extrusion.

You pretty much have to DIY epoxy granite. You probably get a better machine that aluminum extrusion (which are not meant for machine parts). You can DIY cast iron as well, but the high temperatures scare me away (and I done al casting in my backyard)

Have you tried metal 3D printing? Is that a thing for home hobbyists?

Those machines are still really expensive, and I haven't seen any versions that aren't a giant pain in the rear to setup and run. (spent several years setting up and rubbing prints on metal 3d printers.)

Which 3-D printing process were you using, and why did you rub the prints?

Compared to plastic 3D printers, metal 3D printing ones are at minimum 100x more expensive, if not 1000x or 10000x.

It is to a certain extent. I forgot the exact brand but they give you a spool that’s $100-200 for 500g but that includes an autoclave service. You can ship the part to them to fire up in the furnace. But realistically, it’s cheaper and easier to outsource this whole thing.

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