[james_III]

Yes I know original version of GRBL will not support and there are many issues with UNO board. I'm starting to make bigger is better tabletop cnc machine ASAP and it would be really handy to have 4th axis. Some goooooggling later I found something that might actually work.

https://www.rcgroups.com/forums/show...plete-Solution

https://github.com/fra589/grbl-Mega-5X

https://github.com/LETARTARE/grblQ-Mega-4axes

https://github.com/gnea/grbl-Mega/pull/21

Clearly something is going on, but can't really find any experiences of these and information what goes where is somewhat limited. So anyone over here have any experience on extra axis? Seems like it might work.

[hfjbuis]

James,
No response until know, Isn't downloading and try it your self not an option?

[james_III]

James,
No response until know, Isn't downloading and try it your self not an option?

With you and me, there is this miscommunication thing going on, not the first time. Yes of course I'm downloading and testing, this is just my bad habit to ask possible information before jumping on the deep waters. Maybe I should stop such behavior, just use goooogle and keep all to my self.

[skrubol]

It's probably just that this Arduino forum isn't very active. Most on here are running bigger machines with commercial controls or PC based (Machx or LinuxCNC.)
Is your 4th axis going to be a rotary axis? Rotary support from the motion controller isn't strictly necessary, but is definitely a nice to have. A couple things with typical rotary support are understanding rollover (that 360 deg is the same as 0), and feedrates that make sense (G93 usually, which uses time for the move rather than speed.)

[james_III]

Bench testing this https://github.com/fra589/grbl-Mega-5X Response for testing is good, it is very limited what can be tried without connecting to actual movements. But no instant error on basic things, so I shall proceed. Biggest issue is to split Y direction stepper pins to drive two stepper drivers, but this was expected. So it is nearly 6 axis

[shooter64738]

I may be a little late to this convo. If you are looking for a 6 axis version of grbl, Heres is a version I have on github.
https://github.com/shooter64738/grbl-6-axis-synch