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hercek
In such a position, the horizontal pair does not need to prevent rotation in the horizontal axe perpendicular to it (other two arm pairs will do it just fine). The horizontal pair still needs to prevent rotation along vertical axe (which would lead to smaller platform tilting too). Maybe you are right and these positions are significantly worse even when arm pair distance is big enough but I have doubts without proper momentum propagation analyses.
It's not really an issue when printing, the problem is when you are trying to push the effector down and activate a switch. You have no leverage on that one side of the effector allowing it to rock and no, the others do not compensate. I was getting about 3mm deviation because of it.
The worst part though, was that you just lost 1/3rd of your load bearing pivots, and the other take all the abuse. After a few hundred iterations my ball joints were junk.
You are right, it's good because you get a heck of a level build plane, I get fantastic prints from it, I hadn't really thought of that.Quote
sheepdog43
* you say this is bad because small calibration errors lead to big effector errors at bed edges;
* I say this is good because the small calibration errors can be detected at the edges (and thanks to that we can correct them).
However, it takes a lot more effort to get there.
In Rich Cattel firmware I had to run the calibration it in stages or it would never have calibrated.