Shapeoko & Nomad - Feeds & Speeds Charts

(William Adams) #41

Worked up a basic chart:

We’ll all have to fill this in when we get a chance.

(Aidas) #42

Thanks @nick and @WillAdams !


The Nomad Speeds and Feeds chart specifically calls out the “Nomad 883 Pro”. Is there a comparable chart for the original (non Pro) Nomad 883 (i.e. the Kickstarter model)?

(Apollo Crowe) #44

The Nomad Feeds and Speeds chart applies to both machines.

(barthelemy bach) #45

hello every body, juste one question, all the speed and feed chart are calculate for a 1/4 end mil flat and ball nose but my question is how calculate all this setting for a 2 flute 1/8 flat end or 1/16 end? thanks!

(Richard Cournoyer) #46

Use an online machining calculator to determine the Proper SFM (Based on the numbers from the chart) THEN recalculate the NEW speeds (Spindle and Feeds, etc) based upon the NEW cutter diameter. This is how the system works.

Something I do daily and have never broken an end mill, and I use 1/4 to 1/32 cutters on all material (wood to steel)

It does take a little time to get used to the math, but with a little practice, it will become second nature. NOW once you have the NEW speeds and feeds, AND they work, write them down. For me a Fusion 360 user, I have a home tool catalog inside of Fusion for 3 basic material (Wood, Aluminum, Steel) that contain ALL my cutters. The speeds and feeds are now adjusted, so all I need to do is select a tool and material, and will always have the correct speed and feeds.

It would be SO nice to be able to adjust the Tool Catalog inside of Carbide Create to allow us to also be adjusted…someday.

Extrapolating speed and feed rates
(William Adams) #47

FWIW, I used a calculator to do those calculations for the Nomad at:

I’m hoping to eventually get around to doing this for the Shapeoko so that we can fill in the 1/8" speeds — but I believe there’re some inconsistencies in the numbers which I’ve pointed out to @ApolloCrowe and @edwardrford (to be fair, the latter still seems to have it on his “to-do” list judging by the open ticket) — there are also some typos which drive me to distraction (yeah, Titivillus is my mortal enemy). I’d really like to have the canonical, master source and single point of control for these things be spot-on before doing anything further.

Okay, while we’re on this. List of thoughts / questions / queries / concerns / typos / whatever:

  • Acrylic — cast or extruded?
  • Polycarbonite — SPOK? Polycarbonate?
  • Carbonfiber — SPOK? Carbon fiber? — shouldn’t Garolite and G10 get similar health cautions?
  • Foamcore — SPOK? Foam core? — what is this stuff, where does one get it and what is it used for? Do we mean the paper-backed stuff from a craft store? Won’t the paper dull endmills?
  • Lead — why is this listed, do people cut it, shouldn’t we note the potential hazard and bio-accumulation risk?
  • Mahogany — 3.5.5 on the Makita speed dial?

(Jarrett) #48

Are those calculations simple algebra? I’d be willing to code it all up in a web app if you tell me what formulas/variables need to be applied. I’ve been waiting for a 1/8’ endmill chart for the Shapeoko, but if I can help get it done faster and make it adaptable for other endmills, I’m happy to put in some work towards it.

(William Adams) #49

Not even algebra, they’re very simple formulas.

Chip Load = feed rate ( ipm ) ÷ ( cutting rpm x number of cutting edges )

(from: but I think it’s also on the Wikipedia article)

As noted, I used a set of simple on-line calculators at: — fswizard has become an app and the free on-line calculator was taken off-line last I checked.

(Scott Conant) #50

used for scratch build rc airplanes. The surfaces could be paper or poly (2mm - 6mm thick) Also Depron which I think is extruded polystyrene.

(Jarrett) #51

So, I’m a bit confused.

If I take the formula:
Chip Load = feed rate ( ipm ) ÷ ( cutting rpm x number of cutting edges )
and apply it to the numbers given for MDF on the S3 feeds & speeds chart:
80 ÷ ( 17000 x 2) = 0.0024

On that same page (, it lists that the chip load for .25" on MDF should be between .013 to .016. So this doesn’t add up–it’s off by 50x.

But, even if the chip load numbers matched, can this formula even be used to convert the numbers from 1/4" to 1/8" tools? It seems like the chip load isn’t transferrable from one to the other. Also, this gives you RPM and Feed on the chart, but what do we do to figure DOC and Plunge?

Sorry if I’m totally misunderstanding what’s possible here.

(William Adams) #52

Still learning this stuff myself.

One issue with the chipload charts as I understand it is they’re intended for mills and low RPMs and high torque and far more rigidity than our machines have AIUI.

(Jarrett) #53

Ok, that makes sense that the S3 needs a more conservative chip load. But, is there a formula to take the known chip load from 1/4" and figure out the 1/8" settings needed?

It looks like the pdsspindles chart roughly lists the 1/8" chipload as around a third of the 1/4" chipload. Do you think simply dividing the feed rate by 3 (so, ~27) and keeping the RPM the same a good way to start?

(William Adams) #54

No, as I understand it, to reduce chipload you would reduce RPM (but that’s wrong? see below) — managed to melt a glob of HDPE onto a 1/8" endmill not thinking about that and using the 1/4" feeds and speeds.

We do have one pair of data points for 1/8 vice 1/4:


  • 1/8″
  • Depth: 0.762 mm
  • Speed: 17250 RPM
  • Feed: 762mm/min
  • Plunge: 254mm/min


  • 1/4″ #201 or #202
  • Depth: 0.76 mm
  • Speed: 17500
  • Feed: 762
  • Plunge: 254

Hmm, never noticed that they are essentially the same. I’ll have to dig out my notes on the 1/8″ cutting — used the same file, so pretty sure I just reduced the RPM.

@ApolloCrowe any possibility of resolving all this and getting an official feed / speed chart to support Carbide 3D selling the 1/8″ precision collet for the Dewalt?

FWIW, I’ve always wanted to see a CAM feed rate tool which was dynamic and physics-based, and which could adjust spindle RPM on the fly for machines such as the Nomad, calculating material remaining with each spindle revolution, dimensions and heat load of each estimated chip, based on the content of a G-code file.

Obviously need to research and work up a basic understanding of this ex nihilo. Here’s a start:

The formula to calculate your chipload is: Feedrate / (RPM × # of flutes). To increase chipload: increase feedrate, decrease RPM, change to an endmill with fewer flutes. To decrease: decrease feedrate, increase RPM, change to an endmill with more flutes.*

(Jarrett) #55

After reading a little more, I feel like we’re skipping a big step of not getting the cutting force figured out first. Accuracy, speed, and prevention of broken endmills are more important to me than chipload (which is just wear reduction, right?). I feel like having a formula that takes in janka hardness and a desired chipload could be enough to get decent settings, but I’m over my head at this point as to what that formula would be and the S3 datapoints to support it.

Back to chipload: since a lot of the settings for the 611 are already at dial 1, reducing RPMs isn’t an option on many materials.

BTW, could you add an “or” to that definition, i.e., “increase feedrate, decrease RPM, or change to an endmill with fewer flutes”?

(William Adams) #56


Yeah, calculating the cutting forces should be a factor in this — if they get to a point where they’re significant — I had a belt slip while cutting Ipê and the machine powered through a full 1 inch depth cut just fine.

Arguably we should all just get a copy of G-wizard — though I was a bit taken aback by this note on the Shapeoko settings in it:

More germane to our current discussion here, /u/aboqsa went on to say:

Related to 1/4" -> 1/8" mills. I’ve had this issue a lot too. Probably the most important thing I’ve noticed is that the step down in chip load from 3/4" to 1/2" to 1/4" is fairly linear. However, 1/4" to 1/8" is roughly double the step down. I assume this is because mill deflection is finally becoming a serious factor.

(mikep) #57

The note on reddit isn’t -totally- wrong. It seems to take a little black magic to hit the exact right setting, but I haven’t had G-Wizard give me anything just crazy. To the posters point, 16K -IS- too fast, and the software is basically telling you that the cut you want isn’t possible to do well with the tool and other settings you’ve chosen. That’s not wrong, but it could be more clear.

If you’re really trying to avoid broken endmills, g-wizard provides some good input. Far better than you can get from just guessing. The Carbide speed+feed chard is a good starting point, and matches up well with a few spots that I’ve checked against g-wizard, and g-wizard had dramatically dropped the number of broken and chipped endmills I’ve produced :slight_smile:

Honestly, after putting well over $1000 into the cnc mill, spending $80 (it goes on sale pretty often, just keep an eye out) is a cheap investment in reducing tool breakage. It is a weird tool, could use some UI design, could be a lot friendlier, has a steeper learning curve than it needs, and isn’t very well documented for the newcomer… but all that said it’s still the best tool I’ve found that I’m willing to pay for.

There -are- free tools on the web for calculating speeds and feeds, I think they’re in the SO Wiki (Will points to these all the time, so I’ll just skip it)

(William Adams) #58

Yeah, the thing is, I’m still stuck in the project’s original opensource roots — I use Carbide Create/Motion and am learning MeshCAM 'cause they’re “free”, but I’d be much happier with opensource, if for no other reason than I just don’t want to go through what I’m currently going through w/ Freehand for any other software (hanging back on 10.6.8 for Mac OS X, fretting with each patch / upgrade that the app will quit working on Windows).

And, I’d like to understand all this well enough that I would be able to make effective use of G-Wizard if I chose to get it.

There’s a new thread on this here:

and I’m going to continue all this there, since we’re getting away from the official charts.

(mikep) #59

Fair enough. Would be nice if there were some more tools out and about.

(Stephen Kidwell) #60

Why did you not just link the actual charts?