I’m interested in the opinions you have on the three CNC machines:
Shapeoko 3
http://www.shapeoko.com/
X-Carve
https://www.inventables.com/technologies/x-carve
Routakit:
https://www.routakit.com/
What do you feel the strengths of each are and weaknesses. How do they compare to each other. Have you used one or more of them?
Thanks.
I like them all, but they are priced differently and in the range of rigidity. What are you looking for?
Why not just build one?
Well, the Routakit is new to me but after looking I am not that impressed. If I had to choose between the three, it would be stronger towards the Shapeoko 3 for rigidity or the larger size xcarve for size.
I don’t really see that much difference in them as far as price or configuration when comparing similar size. Can’t say that there is that much over the turnkey Chinese cnc router-engravers off ebay on the smaller sizes. The price of the larger isn’t that much off a full turnkey system like the ones from Probotix if you add in the cost of a controller PC that is included. If you are looking for doing more metal and work envelope is not that important, a CNC Taig can be down in the same price range from DeepGroove.
I have the X Carve 12" and it is a very nice and inexpensive machine.
It is expandable and modifiable. Plus it has some decent online software, simple but good.
It is easy to assemble if you have basic mechanical skill. A small solder iron is needed.
I recommend it, I looked at many before I bought this one. Get the bigger step motors for power.
That help?
I think the SO3 and Xcarve are both nice - SO3 for more rigidity, and I’d go with Xcarve for the first class support from @Inventables and the community there.
Very interesting, I appreciate all your opinions and experience. I’m looking for something that is larger, something that can be expanded to to do large sheets of plywood. Not necessarily full 4x8 sheets but at least 6’ long and 4’ wide. Possibly something that could be used for building WikiHouse based buildings yet capable of smaller projects such as layered single driver horns (speakers). I was leaning toward the Routakit thinking it was the most rigid but comments above seem to lean away from Routakit. Maybe it’s because it’s new and not many have experience with it yet.
As I understand it, X-Carve and Shapeoko CNC machines have a common lineage. Is that right? While they are different, isn’t one a spin off of the original Shapeoko line of CNC machines while the other is continuation of that line? Or am I completely wrong?
If you want to get up to large size inexpensively and you don’t have the facilities to fabricate your own parts, I would suggest the bearing blocks that CNC Router Parts sell and use mild steel for rails.They have a 2x4 kit that is in the same price range (without electronics) that is going to be a lot more rigid than the ones you were asking about. They sell all the parts a la carte as well.
Here is a nice build that uses wood instead of AL extrusions. https://youtu.be/WGZvk1RVWXA (part 1 of 23 
)
Get up to 4’ axis range and you are a lot better off with direct drive such as rack and pinion, belt or chain.
Just have a shop do it with a waterjet if you want to cut the parts out of aluminum. They are cheap and quick as long as they are in business for themselves.
To build one really only takes some repeatable pieces.
If you build it out of wood you’ll need some really good wood and a glued design to get real stabilty.
It’s hard to find truly good wood.
Check out the latest YouTube videos from @frank_howarth . He is building a CNC machine that might be what you want.
The SO3 and the x-carve have a common history : the SO2 and the x-carve are very similar with the x-carve being an upgraded version of the SO2. But the SO3 was sort of a complete redesign and made by a different company.
Slightly off topic. Have you checked out http://openbuilds.com?
Looks like a great resource. Thanks for the pointer!