Good Concentric Test


While I still consider myself a CNC noob, because I know I still have much to learn, meaning I don’t know how much I have yet to learn :grinning:, I figured this little design is a very good test for concentric circles.

You may recognized the design from a recent TV show trinket/prop. Its designed to be milled with a 1/4 bit, but you could do it with a smaller bit, it would just take longer.

As seen, it was carved in pine and its roughly 8 inch in diameter.

I used very conservative feed and speed: 13,500 rpm, DOC 4mm, Feed 200 mm/min, 2 flutes 1/4 carbide bit.

See attached stl, and find the original exported Fusion 360 source. I placed a 6mm bearing ball in it, and my 5 year old loves to play with it.

Friends of the TV show surely will enjoy and yourself curse at it if your machine is not completely fined tuned.



WestMaze.stl (191.9 KB) (181.0 KB)


Looks good, I’ve tried using the carbide3d feed & speed for pine before and it felt rather aggressive, may try your numbers next time I have somethingt o cut.

Thank you.

Being rather clueless about feeds & speeds and finding the Shapeoko feeds & speeds chart rather unsatisfactory, I tried G-Wizard Calculator.

Its not that expansive, and coupled with Fusion 360 cam preview, it helped me understand quite a bit (pun intended).

They have a 30 days trial. Worth taking a looksee.


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And, if you’re not satisfied with those numbers, there are even more on the wiki.

With materials which can have a range of characteristics, or which exist in multiple forms (white pine vs. southern yellow pine), it’s best to always do a test in scrap material first — another reason to look forward to Grbl 1.1 (feed and speed over-rides).

g-wizard goes on sale from time to time too, and is an even better deal when it does.

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Another important consideration is that for a hobbyist, one merely needs one or two HP — the app has an elegant licensing model: annual payment gets one unlimited HP, if one stops paying, then one gets a light version rated for the number of years as HP, so a two year payment gets one 2HP in perpetuity.

That said, I wish Carbide 3D would license it and build it into Carbide Create — there’s already a nifty integration (was? maybe it’s broken?) with MeshCAM where one can copy-paste from G-Wizard into MeshCAM.

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WillAdams that would be nice. As I casually glance at 3d printers some of the tools look a little more developed, I mean it’s a different animal but sometimes it seems like potentially important-for-safety information is obscure, heavily opinion biased, or behind a pay wall. I know there’s a million different combinations of end mills, spindles, machines, etc, but be nice if I could plug in some of the more common scenarios and get a good value that is both safe and not super conservative.

Here is an svg of it aswell. (


That’s the reason I bought the Meshcam + GWizard, but it doesn’t function anymore, or never did? I still use them both, but it kinda bothers me still that what is claimed on the outside of the package isn’t in the box. Maybe it will be fixed in V7, but since I bought the standard license of MC I’d lose real estate on my XXL with the update which limits it to 24"x24". Really wish there was a final fully functional version of MC V6 as I don’t need the added functions of a Pro license, but V7 will be kicked in the knee so to speak for those of us with a standard license.


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Bummer. Added notes on this on the wiki.

EDIT: While it’s neat that the Nomad folks automatically get MeshCAM included with their machines for the purchase price (not free as noted by @mikep), I wish that there was more integration — say an intermediate license which would allow Shapeoko owners to buy MeshCAM, and some upgrade option for those who own both machines to either automatically, or as an option to upgrade, get that intermediary version.

Similarly, I wish they could work out a licensing agreement to get a 1.25HP version of G-wizard lite for Nomad/Shapeoko — or that some other feed-speed calculator intended for hobbyist use would come along.

My dream program would be one which would:

  • accept a 3D model of your machine
  • load your G-code
  • do a full 3D simulation of all the physics, incl. an estimation of what size chip might be cut with a revolution of the spindle at a given speed at any given point in the cut

and would then calculate optimal feed rates, and spindle speeds for every portion of the cut — I think an application like that would be a real game changer for the Nomad, esp. if it was paired with a system for positional encoding so that the machine would know when it missed steps.

I also suspect that even on today’s systems it would require a cloud-backend w/ specialized processing.

That would be cool for sure. For the GWizard side when I was trying to decide what license to buy, since there’s no 1.25HP license I exchanged a little bit of email with the folks in the QWizard camp and decided on the 1 year unlimited and 1HP forever license. Reason being is that you rarely see anything above 1HP on a machine like a SO3. It’s kinda like all of the special tunes out there for my motorcycle, I could spend a bunch of money getting another 3-5 hp at the back wheel on top of the 103hp I already have, but I would never notice the difference unless I was racing and someone beat me by 0.25 seconds. For most of what I do I usually only see a fraction of 1hp to begin with, so why buy more license than I need? On the Meshcam side I’m not saying because there’s some broken functions (speeds and feeds paste, show full program zero) that it’s a horrible product, it isn’t, it does what it’s supposed to do for the most part, it’s just the current release is somewhat broken and the next release removes some functionality and requires payment to get it back. I’d honestly like to see more happen with Carbide Create though, seems like I’ve been using it more and more. While I have a high end CAD bundle that can export .stl and import into Meshcam, I find it really simple to just make 2.5D stuff in Carbide Create, just wish the sketcher was much more robust.


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:hot button hit:

Nomad users don’t get “Meshcam for free” - they buy a package that includes a license to a limited version and a milling machine. There is a big difference between someone walking up to you and handing you something without expectation of payment, and something that is listed as a value-add feature of something you purchase.


Good point. Should be rephrased as:

While it’s neat that the Nomad folks automatically get MeshCAM included with their machines for the purchase price.

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I’ve inquired in the past about the notion of a lower-cost Meshcam license for Shapeoko purchasers/clients… no replies

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What steps are needed to get this project into carbide create?

I got it to load,I have a toolpath to pocket it,whats my best aproach to get it cut out after the pocket path?

To cut things out, use an outer profile path:

Toolpath | Cutting Depth: check Use stock bottom (we want to cut all the way through) | Offset Direction: Outside / Right

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Still cant get it,idk why cc hates me so much but im almost over it.

Post the file? Preferably the original source, and the CC file?

I used the file that was in this post put it back into fusion360 and got an output cc would reconize,I was able to get a pocket at one point but couldnt get the cut out path to work
mazecc.c2d (2.6 MB)