Testing More Aggressive GRBL Settings

I’ve previously used $122=200 before with good results with the HDZ. I backed off after I checked with Luke but I never had an issue with it at 200.

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Interesting. I’ve been running with it $122=400 for over a month now with no issues. It’s what I ran on my prior z-axis so I just carried it over. Am I missing something that anyone sees when it’s that high?

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Awesome @wmoy

Will be updating the XXL at work accordingly
Figured there was some speed left and appreciate you doing the legwork.
Particularly fond of the non engagement travel speed increase


Not sure honestly. I started with both feedrate and acceleration high, and brought them down in tandem. Have not tried high acceleration with the more moderate speed. If it hasn’t been problematic for you though, great.

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Does CM still allow these to be set directly? I used to manually override these in earlier versions (CM3, etc) but haven’t in a while since it added the automatic machine setup and even lets you click if you have bitsetter and HDZ. I guess I should write all these settings to a file in case I accidentally update it again.

I have never understood why the default settings in CC and CM are so painfully conservative - I just assumed it was because the Nomad is Rob’s first baby and he didn’t want it to see that much less powerful than a Shapeoko :slight_smile:

People still manage to get themselves in trouble with the stock settings. C3D has traditionally erred on the side of too many training wheels rather than too few.

You can program in new GRBL settings in the MDI interface in CM.


For the sake of illustration, here’s a (very, very bad quality) video about how my SO3 behaves with those settings:

I never bothered to tune them before, but I must say this feels like I have a new machine. Go and upgrade those settings now !


Hey Julien. I made all the GRBL changes, double check with log files, all seems good , but no changes happened:( Am I missing something?


Would love a setting in CM to switch to these more aggressive grbl settings.


Weird. I did my test using CNCjs, not CM, but I don’t see how that would affect the results.
You don’t see any change in either jog speed or homing behavior ?

Yes, I used CM and didn’t see any diff in either job speed or homing:(

Anyone else have this issue?

I have not tried yet but @wmoy specifically said CM so he must have tried using CM. JUst for the sake of completeness, what version of CM are you using?

CM Version 4.0.428. Maybe works only with beta?

Not likely.
By any chance, did you mistakenly click “Send Config Data” after your changes ?

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431 is the current version.

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Weird, on Mac OS and says “no updates available”, will have to download…


I don’t think that Mac O/S actually looks for updates of Carbide programs, you have to go manually to check if any are available. https://carbide3d.com/carbidemotion/download/

Aaah, GTK, thanks!:slight_smile:

No. You can send GRBL settings with basically every version of Carbide Motion since the beginning of time. If you send “$$” to print the settings in the log and you don’t see the changes, then something is wrong.

You won’t see much difference when you jog. Jogging speeds seem to cap out at 6000 mm/min currently when commanded through the CM UI. You’ll notice it in movements commanded via gcode instructions, ex. “G0 X0 Y0”.


When I watched Julien’s vid, it looks like his SO3 is on steroids!. Mine is no where close:(