Calibration Problem? Skewed Cuts

I’m confused…

Can you point me to the “frame option we were directed to from links MakerMade has on their website”? You said you selected a square frame model? But then you said this:

And from what i can tell, that’s for the standard bolt-together frame and is what, I think, they would have sent you instructions on.

Maslow’s site sends you here: https://github.com/MaslowCNC/Mechanics/wiki/Choose-A-Frame-Design to determine which frame to use.

I recall using instructions from the same maslowcnc.com website. However, the instructions we printed from those links were not especially thorough so my partner had to find a few videos to fill in the gaps. Later, MakerMadeCNC sent a different set of instructions for setting up the Maslow than we’d used. Those instructions had details the other online instructions missed and helped us get to the next stage of problems. I didn’t keep any of those materials because I’ve been trying to focus on moving forward from our current problems.

Here is the second video showing non-squareness from a different perspective and other skewed results.

Can you post both a picture of your frame as well as the contents of your groundcontrol.ini file.

How do I get a picture of the contents of the groundcontrol.ini file?

by doing a screenshot?


This doesn’t have “contents” … but here is the screenshot.

Dear, you have to open the file with a text editor first, then do the screenshot … but this might require 2-3 screenshots as the file is longer than the screen …
Just open the file with a Texteditor, mark all, copy to clipboard and paste into a reply

That’s what I needed to know.

Here it is:

[Computed Settings]
distperrot = 63.5
kpposmain = 1300
kiposmain = 0
kdposmain = 34
propweightmain = 1
kpposz = 1300
kiposz = 0
kdposz = 34
propweightz = 1
kpvmain = 5
kivmain = 0
kdvmain = 0.28
kpvz = 5
kivz = 0
kdvz = 0.28
chainoversprocketcomputed = 2
fpwmcomputed = 3
kinematicstypecomputed = 2

[Maslow Settings]
bedheight = 1219.2
openfile = /Users/drewbriney/Downloads/Copy of Copy of Untitled.nc
motoroffsety = 441.325
sledwidth = 197.0
zaxissafeheight = 5
bufferon = 0
bedwidth = 2438.4
comport = /dev/tty.usbmodem144101
macro1_title = Macro 1
sledheight = 441.325
macro2 =
macro1 =
zaxis = 1
sledcg = 74.4
macro2_title = Macro 2
colorscheme = DarkGreyBlue
zdistperrot = 3.17
motorspacingx = 2988.08

[Advanced Settings]
rotationradius = 140.0
chainextendlength = 1650
kiv = 0
gearteeth = 10
spindleautomate = None
kdvz = 0.28
chainsagcorrection = 43.746718
chainpitch = 6.35
chainlength = 3360
propweightz = 1
zencodersteps = 7560.0
maxfeedrate = 800
enablepospidvalues = 0
rightchaintolerance = 0
enablevpidvalues = 0
maxtouchprobeplungedistance = 0.0
kpvz = 5
kdposz = 34
chainoversprocket = Bottom
kpposz = 1300
fpwm = 490Hz
kdpos = 34
encodersteps = 8113.73
truncate = 0
homex = -44.17
homey = -15.36
kinematicstype = Triangular
kipos = 0
kdv = 0.28
kiposz = 0
digits = 4
kppos = 1300
kpv = 5
propweight = 1
positionerrorlimit = 2.5
kivz = 0
leftchaintolerance = 0

[Ground Control Settings]
zoomout = pagedown
centercanvasonresize = 0
viewscale = .45
zoomin = pageup
validextensions = .nc, .ngc, .text, .gcode

[Background Settings]
backgroundfile =
manualreg = []

@buhlig, could you post your groundcontrol.ini file as well, for comparison purposes.

Here is the frame - it has some boards in front it but you can see the set up just fine.

Yeah, that looks like a fairly standard frame… anyway, two common things that can cause cuts to be thrown off are bad the calibrations and chain skips. A chain skip is where a link slips on the sprocket and now the chain length isn’t what the controller thinks it is. This can make cuts *off". To fix the chain skip, it’s best to reset the chains. There’s a wiki on how to make it easy do the reset in the future. You’ll need to change your extend chain distance to 1651.

That’s good to know. You already had me reset the chains and I did it before the last cuts (which were off like the ones in the video). Also, the sled was about 12" higher than it showed on ground control. I can reset them again, but I think that’s not going to be the full solution.

If the sled is higher that much, then that’s an indication of what the problem is.

If your distance between motors, 2988.08 mm is correct (which seems to be reasonable for a 10-foot beam) and you extend the chains 1650 mm (your setting from above) per the procedure, connect them to the sled and the sled is 12 inches higher than what is shown on the screen, then that points to a problem with the “distance above workspace” setting (aka, motoroffsety). However, your setting (441.325 mm) seems to be a reasonable number based upon the picture… certainly not off by 12 inches.

So, I’d ask that you do the following and reset the chains:

  1. Set extend chain distance to 1651 mm.
  2. Go to Actions->Set Chain Lengths - Automatic.
  3. Set each sprocket vertical and press ‘set zero’.
  4. Extend the left and right chains using the ‘Adjust’ chain buttons.
  5. Connect the chains to the sled
  6. With a marker or nail polish or something, mark the links that are sitting on each sprocket’s top tooth. One tooth should be perfectly vertical if everything went well in extending the chains.
  7. Take a picture of where the sled is.
  8. Press Move to Center.
  9. Take a picture of where the sled is.
  10. Post pictures

Also, looking at the picture I have a question regarding the bungie cords. Where do they attach to the sled and is there any chance that the rolling brackets hit them? From the picture, and though its hard to tell, they look like they are attached to the ring. If the brackets do hit them, it will throw off the triangulation and cause issues with cuts.

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For some reason, I’m not getting messages on this thread so I saw your message AFTER I made some progress. I’ll try taking pictures as suggested but until then …

I manually recalibrated using the nail polish procedure you told me about in a previous thread. I also did this directly before posting this thread (as I mentioned in my original post (#5)).

The bungee is attached to the bottom of the 2x4.

After I recalibrated, it had some problems with the Z-axis and sent me to the “Not Keeping Up” page. A 3000 error limit didn’t change anything - error message persisted. So, I closed Ground Control and reopened it and it stopped giving me the sled error message. The sled moved as it was supposed to using the direction buttons on Ground Control. Hurray.

HOWEVER, the bit was a little far from the workspace so when I tried to tell it to lower .1" (see attached screenshot), it moved the sled 8" higher on the workspace but did NOT move the Z-axis. I thought that was weird so I tried the “plunge to -0.100” button instead. That raised the sled again. I typed that correctly. It didn’t move the Z-axis at all. It moved the sled. That would account for the error I posted above where the sled was trying to move off of the workspace instead of where it showed “home” position was on Ground Control. Thoughts?

I’lll still work on those pictures.

Before I tried recalibrating again, I got curious if I could just move the Maslow to where the fingernail polish was properly set again (it’s only been a few moves since I recalibrated it) and it hasn’t moved very far (only a few inches away from both the right and left motors). Might as well have some fun, right? I thought it might be a worthwhile test anyway.

My computer is to the right of the workspace so I never get to see what it does very well and I wanted to see how much Ground Control directions were moving the chains so I could guesstimate where to move the Maslow to get it back to where the nail polish was where it was supposed to be.

I got a helper. I’m glad I did. When we tell the Maslow to move vertically UP 3 inches (not diagonally - straight up), it moved the Maslow about 5 inches diagonally up and toward the left.

Are you sure the motor cables are in their correct sockets on the Arduino repectively shield?
The middel socket is for the Z-axis …

Where did oyu connect the power supplies cable, to the upper or lower socket?

Yes - the Z-axis is in the middle socket. All motors pass when tested. When the Z-axis is tested, it doesn’t spin BUT says it passes. When I tell z-axis to lower from Ground Control, it moves up diagonally on the workspace each time I tell it to lower the z-axis.

I only see one place for the power supply to fit AND deliver power. I plugged it in the other spot to check but that makes all of the motors fail.

I closed Ground Control and reopened it. The Z-axis no longer moves the sled, but it still isn’t spinning or moving the bit. It seems closing and re-opening Ground Control fixes a great many things …