Define Home is not staying centered in ground control 0,0

Hi, We’ve been having trouble with our CNC machine. We’ve recently had to adjust and center the sled and put those centered measurements into ground control yet its not syncing up. We pressed the ‘Define Home’ button several times. Closing the app and opening it again, it would match up but after a few seconds, the red dot would move lower and more to the left of the 0,0 axis. Is there any way to fix this? Thanks in advance.

Can you tell us more about what this means? There shouldn’t be a step in the calibration process where you center the sled and then enter some information into Ground Control, I feel like that could be an issue.

The center on the board does not match up the center on the computer program. I’m trying to figure out a way to center it without taking it apart and recalibrating it.

If you machine reports it’s position as 0,0 but the sled is actually to left or right of center, then, either, the center is not directly centered between the two motors, or, the chains aren’t precisely the same length. If the latter, resetting the chain lengths would fix it, but you may need to recalibrate it if it was calibrated with the chain lengths wrong. How far from center is the sled?

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Its actually the opposite. It’s centered on the board but on the program it is way off of the center

Well, it’s just two ways to look at the same thing. How far off from center is the sled?

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The sled is centered
The ‘sled’ on the computer program is not. It goes about a foot and half off the center

However, when you press the go home button the sled moves deep into one of the corners and that’s what they consider it home.

If it’s a foot and a half off, then I think your chains aren’t correct. I recommend resetting them and probably recalibrate.

Done that

Do you think you could give us a photo of the machine and the screen of the computer? We might be able to spot something helpful

When you follow the procedure to reset the chains, the motors spool out exactly the same amount of chain. The amount spooled out equals the value in Settings->Advanced Settings->Extend Chain Distance. Since the exact same amount is spooled out, once the sled is attached to the chains then the sled will be really, really close to exactly in the middle between the motors. There have been numerous issues in the past with people getting confused by the instructions during calibration resulting in chains not extending correctly. If you go to Actions->Set Chain Lengths Automatic and follow the procedure and don’t end up with exactly the same chain lengths, then you may have a hardware issue.

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I’m currently going through the exact same issue.

I thought the same as aquamarine303, there really should be a “Re-center” button, but I understand if that doesnt exist.

But it makes a hell of a lot of sense to have that, and im sure it would have been added if it were possible.

the problem is that if the machine thinks the chain lengths are different from
what they really are, you can’t just say ‘now you are at the center’ because the
next movement will do the wrong thing because the machine’s belief of where the
chains are is different from reality.

resetting the chains to a known length is the best that we can do to re-center
the machine.

in the case described here, it sounds like the chain was taken off of the left
sprocket after the measurement between the motors was done. That’s a common
mistake to make.

David Lang

There actually is a button for that. If after you go through the Set Chain Lengths Automatic process, the sled will be placed in, for lack of better term, “chain reset position”. If you find your position in ground control or webcontrol doesn’t match where the sled actually is, you could theoretically jog the machine to the exact same “chain reset position” and then click Set Chain Lengths (Manual) (or whatever its called in ground control). The difficulty will be getting the sled to the exact “chain reset position” and it would be much, much easier and quicker to just reset the chains following this procedure:

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I believe that the Actions → Return to Center button might be what you want, right?


need a way to “recalibrate” center.

but obviously I dont know the details of why thats not possible.

what I did for now is to manually lift off the chains and put the sled back to actual center.

I’m sure this is wrong, but its part of my learning process. ( I haven’t even done my first test cuts yet.)

the proper way is to mark the link on the chains at the end of calibration,
before you move to center that’s over the top sprocket of the gears.

Then when the maslow looses it’s position, you move the sprockets so that one
tooth it at 12 o’clock then move the marked links to this starting position and
tell the maslow to reset it’s chain lengths (the default is 1651mm of chain,
plus the rotation radius of your kit)

so you are close, but not exact.

David Lang

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I’m having the exact same issue with ground control calibration. I’ve read several
Threads and did not seem to find any concrete solution for the sled being centered but ground control being off center.
I am a flawed individual but I believe in honesty very much. This is not a 350$ or 500$ purchase by any means necessary! I find myself constantly working on maintenance issues taking up a very large amount of my time. If you factor in the additional costs of lumber, hardware, router, vacuum cleaner and maintenance, you will find you may have been taken!
I rarely ever get to use the Maslow because it is constantly malfunctioning or tweaking out and running off course. These setbacks are very common! Just look online, the amount of complaints are astounding. These set backs also require more of my time for no reward. The lack of initial instruction for this circus is clearly why there is no contact support phone number, it would always be overwhelmed with people like myself needing help!!
“Open Source” sounds like someone got paid and walked away from the mess they sold you!!
Apologies for the rant but the frustration is overwhelming. I purchased a car once for 500$ that didn’t require this much effort!!

Actually, Open Source means that a lot of people have workedon this project for
free, and spend their time here answering questions for free.

Nobody got rich building and selling anything here, and nobody has walked away
from it.

David Lang


I feel you for sure. I (the original designer) certainly didn’t walk away. I’m here every day answering questions, and I will help however I can.

I actually stopped selling kits for exactly the reasons you describe. Maslow is a totally new concept in CNC and the technology just isn’t ready yet for folks who just want to plug it in and go. My goal when I started selling kits was to make it easier to get a machine up and running (rather than just publishing a parts list and having everyone source their own components). I even had a thing on my website where when someone was checking out they had to read and agree to a thing describing how it was a DIY hobby kit and not a ready to use tool. Even with that in place I still felt like too many people were buying them with the expectation that it would be a Shopbot so I stopped selling kits altogether.

Hopefully someday we will get to the point where we’ll have something more like an office printer where we can just plug it in and get good results right out of the box (not that office printers are all that reliable :roll_eyes:). I think that 3d printers are just starting to get to that point now (after 15+ years of progress).

In the meantime, let me know if you have any specific issues that we can help with. We’ll do our best to sort them out.