# Ellipse instead of a circle

And you’ve done most of the hard work in that you have a machine that moves and cuts! Well done already!

If you are up to it, there is a path that is a little longer, but can save time:

• With GC closed, locate the groudcontrol.ini in your user folder
• Open it with a text editor and compare the following entries with what you measure by hand (better 3 times measured then 1 time wrong {Confucius})

[Maslow Settings]
bedheight = 1222 | measure
motoroffsety = 643 | measure
bedwidth = 2444 | measure
motorspacingx = 3501 | measure
rotationradius = 140 | ring 140

• Now start GC and calibrate but skip the ‘pull chain tight’ thing that measures the motor distance. For the other numbers above skip, or enter your masurements
• Close GC after you calibrated and open groudcontrol.ini again
• Compare the same numbers replace those that you think are not close enough to what you measured
• Start GC and cut

Please report back if this helped and also if it did not.

Kind regards, Gero

4 Likes

Awesome diagram. I love it!

I have been looking for something like this Diagram and Step-by-Step Calibration process for some time to help me get my mind around the Benchmarks.

Although it is a bit more complicated than the “Five Cut Process” associated with Squaring Up the Base of a Cross Cut Sled on a Table Saw, the MASLOW Design is unbelievable in its application.

[Maslow Settings]
bedheight = 1222 | measure
motoroffsety = 643 | measure
bedwidth = 2444 | measure
motorspacingx = 3501 | measure
rotationradius = 140 | ring 140

Now: If the Least Likely to require a “Adjustment” is the rotationradius=140" - Which of the others (and in what sequence ) should be changed to cut a perfect circle?

And, BTW, what about the action/reaction to the TORQUE of the Router? How do we take that into account?

Old, Retired Guy in Vermont.

Wallace.l.johnston@gmail.com

Now: If the Least Likely to require a “Adjustment” is the rotationradius=140" - Which of the others (and in what sequence ) should be changed to cut a perfect circle?

whichever one is wrong

this is only half-joking. There are lots of ways to attach things to the
machine, and variations of only a few mm between motor placement compared to
what the machine thinks they are can translate into up to 2x that much error on
the machine.

There is also work to improve the calibration and add additional correction
factors.

So look at those numbers and check to see if the result looks correct or not.

And, BTW, what about the action/reaction to the TORQUE of the Router? How do we take that into account?

We don’t, the torque of the motor should rotate the sled, but sled rotation
should not affect it’s position. The bricks being on the bottom counter the
rotation from torque.

David Lang

1 Like

Welcome, @Wallace_Johnston. There is a LOT of great information in these forums.

The “How To: Get Calibrated!” wiki is excellent. I recommend going through all the wiki pages, actually. Also, dlang’s “List of sources of error”, and these benchmarking related threads: Triangular Linkage Evaulation Criteria and Measurements, BenchmarkAccuracyTest20180716.xlsx and benchmark database, might be of interest to you.

3 Likes

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

Or, maybe I do the wrong clamping?

1 Like

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.

1 Like

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.

2 Likes

@Keith
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.

1 Like

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

2 Likes

By the time i show up, all is answered already 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.

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

1 Like

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 i measured the distance between centers shaft and entered it manual in setting inside GC launched, and it’s looks different with automatic measuring

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)