A question re homing on SO3


(Alan Nicholson) #1

I just ran the homing process . Entered $h22 but when I went to settings it showed x as 420 but Y as 430. I manually changed Y to 420. Changed has homing to true.

Went back to midi and sent $h and machine ran homing but only z changed to -5 . x changed to 236.20 y changed to261.50.

Motors all touched switches and backed off as expected.

Any suggestions on why x and y did not change to -5 as outlined? Should I change them manually?


(William Adams) #2

When you home, the machine will back off the machine origin by the numbers declared in Grbl settings for

$27=1.000

Homing pull-off, mm

the default for that is 5mm (see: https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration and http://docs.carbide3d.com/software-faq/shapeoko-3-default-grbl-settings/ ) so presumably, your machine wasn’t backed off the Z for some reason.

I wrote up my experiences in values for this sort of thing at: https://wiki.shapeoko.com/index.php/SO3_Function_Test#XL but didn’t experiment much with Z


(Alan Nicholson) #3

Thanks Will
I ran the procedure exactly as per carbide 3d article on homing (CM3).
When I switch on the Info screen comes up and shows.Machine Idle no file loaded with toolpath extents for x, y & z as 0.000 Not Homed.
Next I switch to MIDI tab which shows: X:241.20. Y:266.50 Z:0. I send $22=1
I then open Settings which shows settings on lines 1005= True 1006= 420, 1007=420(I changed 420 to 430 manually).
I switch back to MIDI screen and send $h and values change to X: 236.20, Y:261.50, Z:-5.00
It seems the switches are backing off the required 5mm but X & Y are starting from other than zero but I don’t know why. If they started at zero on first MIDI screen it would all be OK and final values all at -5.00 as expected


(Alan Nicholson) #4

I think I have done my usual trick of over thinking the issue. I have been concerned that after homing the measurement on each axis was not -5mm.:confused:

I think the target is to get the homing reading to back off by 5mm from the original setting to prove that it is in fact working correctly.:thinking:

Am I correct…if so on to the next step. Sharpies is attached and ready to go🤗