Off in Y? Chain sag?

I made my top beam ~ 11’ 4" and the chains aren’t long enough to do the pull test. I have entered all calibration but skipped the chain pull section. Used Fusion to create a 300mmX by 1000mmY test gcode file. I am getting about 5mm too short on my test of a 100mm pattern in the Y., X is pretty close. Is there a way (setting) in the setup to compensate for this?

You can manually enter a value for the distance between motors in the settings. Manually measure from outside edge of one gearbox to the outside edge of the other gearbox and subtract 40.4mm. that will give you the distance between the sprockets to enter.


Got that bang on. Is there a drawing for expected measurements on the calibration benchmark test?

Found it!
I’m only 2mm off on X and 3mm off on Y.
I guess thats not bad seems strange thats its farther off on the smaller measurement though doesn’t it?

I remeasured. Average of 6mm off. Mostly in center and top left Y being 7mm and 6mm everything else is within 2mm. :crazy_face:
From upper left its 6mm, 7mm, 1mm in Y (vertical) and
0mm in X (horizontal).
Any ideas why?
FYI the sled is staying level for all cuts.

Does anyone have any suggestions please?

I believe that in general most people have better accuracy in the center area of the board and as they go to a corner it gets worse when bit may rotate etc if it’s not perfectly center (at least that appears to be my problem) hopefully @bar may have some other suggestions for you!

Heres my setup. Used materials on hand but its rock solid despite how it looks lol.
(not sure how to insert a inline picture)

Maybe we need to add a Y axis calibration as part of the setup?
I have re-calibrated from scratch numerous times. I’m running out of scrap! lol
Firmware 1.18
Distance between motors 3391mm

Loaded :grin:

Not related to the issue you are seeing, but you might want to zip your z-cable somewhere on the sled to avoid movement on the z-motor plug. That plug is pretty unstable and movement of the cable can cause unexpected results.

1 Like

Good tip thank you

all those angles on your sled could of easily caught on your multip piece bad can caused an issue. I would redo your sled so it is a circle.

I was watching it the whole time and no snags. I wanted to dial things in before I cut my final sled.

1 Like

It’s a bit difficult to narrow this down, as to my knowledge we have no statistical data on how the calibration reacts to skipping one or more steps. Perhaps it would help to enter the hand measured values in the settings before doing the calibration. This way the motor distance should just stay on the manual entered value and everything else calculated based on that.
After that try and play with simulator in GC to see if you can replicate the errors you are seeing.

1 Like

Is there a way to measure the gcode lines in GC to confirm that its not the problem?
Perhaps the bit is running inside the line, would make more sense seeing tthat 2 measurements are off by pretty much a bit width

Actions/Advanced/Simulation lets you play with simulate error settings and the red lines will show the expected result with this errors.
Can you upload the gcode file you are using?

Not home right now but its just the calibration benchmark that comes with GC

Oh, ok… then the groundcontrol.ini whenever you get the time.

Sure thing. Thank you! I’ll post that tonight

1 Like

Where is groundcontrol.ini?
All I can find is old.ini in GCportable folder and platformio.ini in firmware1.18 folder