If you are running windows it should be in the top level of your user folder (C:\user\{yourusername}
Ok. I’ll check after work. It’s weird that on a “portable” version of GC it isn’t in the GC folder. Kinda defeats the portable aspect doesn’t it? Lol
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Heres the ini file: groundcontrol.ini (1.4 KB)
I guess I’ll try making a new sled to see if that helps. Can anyone explain more detail about measuring CG and if its important?
Also vertical distance from sled mounts to cutter and distance between sled mounting points?
All three of those measurements are only used for the old quadrilateral system of attaching the chains so you can ignore them 
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Ok tried to cut a new sled and this is the result circle should be 450mm
Here is the gcode: MySled.nc (18.6 KB)
Don’t know where to go from here!
I get better accuracy letting the calibration calculate the motor to motor distance. When I measure the motor to motor with tape I had similar error on my circles. I would buy more chain.
Well thank you! I’ll give that a try!
Its #25 roller chain? Is it ok to use master links?
I believe so. I have not done it but @blurfl posted a couple times about using master links that came with the beta kit.
Yes, I’m using them on my setup.
Ok I’ll give it a try. Do you happen to know the maximum spacing of the motors using auto calibration with the stock chains?
Sorry, I cant help. Who's afraid of BigMaslow?
Someone in these posts might have that knowledge. Most of them are using a 12 ft topbar.
I am unsure of how much further apart you would like them to be but I added 18” with a master link to the static side (slack side attached to my frame) and it has been working perfectly for me. Also, I know a lot of people on here are against building multiple sleds, but I found that every time I made an improvement I would change sleds and calibrate again and every time it made the machine better and so I would cut another sled, at this point I have made probably 4? Or maybe 5 sleds. Also, what margin of error are you going to be okay with? Mine is 1/32” off top bottom to left right on a 10” circle. But I have made some great stuff.
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I’m a realist and can easily live with 1/16” as long as I get consistency. Thank you for the tips.
I really appreciate the replies guys. I was loosing the enthusiasm but I definitely don’t mind tinkering as long as I have a direction.
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If you’re in a hurry - You could cheat. Leave the Maslow the way it is and distort your CAD in Y by the margin of error. This is how I operated my first 3D printer.
This will yield fast results. I just incorporated that into my workflow.
After you have a “true” sled you can go back to “tuning” the system. I’m a get Shtuff done sort of guy.
Just my 2 cents.
Thank you
I was considering that but if you looks at the messed up circles it seems a little unpredictably skewed to me. I don’t think the sled is the problem, I got the bit within 1mm from center so I think I’ll try the longer chain and go from there. If that doesn’t work I’ll try moving the motors to 8’. if that doesn’t work I’m screwed LOL
I appreciate the suggestions.
I was having some accuracy issues with my new build, but ended up greatly improving it once I ran the “Compute chain calibration factors”. My chains have been abused (lots of wrapping around sprockets and one has a rather nasty looking twist in it) so I was concerned about them. I had about a 10 mm difference between actual distance (with tape measure) vs. what Maslow measured (extending chains). The chain calibration factors are supposed to adjust for it, however, there’s an issue somewhere with calibration. After doing the “compute chain calibration factors” and recalibrating, I found my accuracy was worse and that the rotational radius was way off (132 mm). If everything is calibrated correctly, the rotational radius really should end up very close to 140 mm. So, I just went ahead and upped the rotational radius (think I ended up using 138 mm) and all the sudden my accuracy was very improved. I haven’t figured why the calibration routine has a problem when chain calibration factors are included. Something to think about…
If you want to try it, perhaps leave the calibration as is (chain sag and rotational radius) and just run “compute chain calibration factors” and do not rerun the calibration after that. It will update the distance between motors and add calibration factors for left and right chain. It doesn’t really make sense (you’d naturally think you need to recalibrate) but it might get you to the 1/16th inch goal as it did for me.
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I think you are close, I really do. I know that I got a little disheartened at first because I felt like I just did all this work and still couldn’t get it quite where I wanted it to be. Is there a reason that you are 12’ apart? (I may have missed it above) I know that I am at 10’ apart and then added extra length so that I would never be at the very end of my length when I cut a 4’x8’ sheet. Picture:
I thought it might help to just add a picture, in it you can also see that since I want to cut all the way to a 4’x8’ that I needed more scrap board so that I had something to mount to for the sled to ride on at all of the extremes.
I am just wondering if the 12’ is throwing it off for some reason (I have no scientific backing on this at all) But it does seem like in your setup it would be relatively simple to just bring your motors in by 1’ each?
I am sure you will be cutting soon! Don’t give up!
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Ok. I just moved the motors closer 10’9" so the chains would reach for auto chain measure. Calibration test cut is bang on in the X 1905 at all points but 5mm off in Y at all points. At least its consistent now but still 5mm off in the Y. Any suggestions to solve this? I’m going to do the circle cuts again now but expect circles will be smaller in Y.
Any chance of devs adding a manual Yaxis adjustment to the calibration?
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How did you do this without it going through the whole calibration procedure again? did you skip steps?