Ellipse instead of a circle

done, step by step 3 times, because I confused the top with the bottom.
has become smoother, however it is still not a circle

will try this solution, but i dont understand, should i only do from the step 9 (aka wiki)? or early?

How close are you?
Do any of the numbers in the calibration look off to you? If so, you can tweak them to try to fix the circle

if they were, I would understand where to look :joy:

Or, maybe I do the wrong clamping?

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I believe you are correct. Change it like the picture from the assembly instructions.

The assembly instruction needs to be updated.

Use the second link. As long as you put the same link on 12 o’clock to feed out, the chain length will be correct.

You are saying to put the second link on 12 o’clock, if using the second link on the ring?

The calibration instructions say to put the first link on 12 o’clock. Due to the safety issue you linked to, which plenty of others have experienced, should we suggest changing the calibration and assembly instructions to use the second link for the ring kit?

We would have to reference different instructions specific to ring and linkage. I use dlang’s metal linkage and must connect to the first link.

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Yes, that is what he is saying.

This has been suggested, but apparently not implemented yet.

I believe @dlang has a solution for this, but I don’t remember where I saw it. He will likely weigh in shortly.


Or, could you do it like @heades has done but use the 3rd, or 4th?, link on 12 o’clock? I like how he put the pin through the chain, which will be safe and prevent the issue that @Gero linked to.

You could. The important part is that you put the same link where it connects to the pulley traveler at the 12-o-clock position when you feed out the chain. The only thing I would be concerned about is whether the link ends up in the same position as when the cotter pin is put between the links. If it does, then you should be golden.

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I’m glad I randomly looked at this thread. I’ve got mine like the OP. I’m just finishing up the build, so no trial cuts yet. Still time to avoid one issue


By the time i show up, all is answered already :slight_smile: Thanks @Keith
My 2 fils:
If you put a pin through the tube, it will at least prevent a swinging sled or might even stop the tube from becoming loose. The red line is the link to put on 12 to feed out the chain and the distance from the bit centre for the rotation radius.

Top-mount kit uses the chain coupler with bolts that are far more secure then a hollow tube.

How i mount my linkage-kit

A picture says more then a thousand words - Pablo Ruiz Picasso

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with the pin through the link hole (rather than through the middle of the link),
the safety issue is not there, so the first link is correct.

It doesn’t matter a lot if you use the second link (and mark it) because the
calibration step should figure out what the rotation radius really is and add
the extra length for you.

David Lang

I didn’t find that file :frowning: i measured the distance between centers shaft and entered it manual in setting inside GC launched, and it’s looks different with automatic measuring :frowning:

and i dont understand in wich position of sled should i measure “Distance Between Sled Mounting Points”, or should i live deafault setting (because in different position it is ifferent setting)

If you are on win, groundcontrol.ini shoud ne in C:/user/{your-user-name}.

My guess that automatic measuring will tell you a shorter distance then you measure by hand, right?
Go with what you measure.

is an old setting for the brackets and not used with triangular (ring). Same for the next 2 under it, so leave as default.

If you make the setting changes in GC, make sure you shut down GC, un- and re-plug the arduino, and restart GC. When GC has restarted, check if the settings you changed are stored correctly.

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nope, longer. On screen there are mine by hands, automatic were about 3070

should I do some calibration throught programm after that, or not?

You can check the dimensions of a circle first and see if it improved.
The motor distance automatic is off by 50mm, that’s the highest error i’ve seen so far, so if you calibrate again, skip the measure part for the distance. What is the rotation radius GC came up with?

emmm sorry, i dont understand?

When you look in the settings in GC, there should be a setting for “Rotation Radius”. For the ring system that you have (judging by the pictures you posted, you have the standard ring system which connects to the chains) I believe this number should be 140mm. The setting might be in “advanced settings”

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