# Calibration of Dual Endstops, confusion?

A little help with the logic behind the calibration of the dual endstop code.

I understand that I start with as BIG a rectangle as I can. And my physical endstops and closely measures as I can.

I drew a 35.355 mm x 35.355 mm square with a fine tipped pen, which should yield 50 mm diagonals.

My “/” diagonal or X1 was nearly 50 mm

My “” diagonal or Y1 was nearly 52 mm

Yay, skew!! Good stuff to correct for. But it appears as though I can tweak my X1 motor stop or my Y1 Motor stop offset, in the + direction. If I slide the X line to the right, my short distance gets shorter… If I slide my Y line Up, my short distance gets shorter.

I would seem to actually need to move the X2 or Y2 motor off their stop to twist myself in the right direction, yes?

A visual would help here

Nick

Yup, so you can move XY1 out a bit, that in turn moves XY2 back.

2mm over 50 is pretty close for a first try, and that is diagonal so that is a compounded/exaggerated number. Nice build!

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“Yup, so you can move XY1 out a bit, that in turn moves XY2 back.”

Crikie if that terminology didn’t make it worse!

SO:

M666 X1 -> Shifts the X1 Motor 1 mm off the X-Min Endstop
M666 Y1 -> Shifts the Y1 Motor 1 mm off the Y-Min Endstop

What command moves the X2 Motor 1 mm of the X-Max (X2-Min) endstop?

Or wait… do you mean that I should then deliberately bump my X2 Endstop physically so that I have the electronic calibration back on the X1 motor? (Push my X2 stopper physically 1 mm forward on the right hand conduit so that the X1 motor is then -1 mm skewed back in effect)

So the way I built this system was by using the pipe cutter to very precisely make 3 identical lengths for my X and 3 identical lengths for my Y. And I mean that was where I spent my effort with a file if needed. When I put my build together, I only then had to insure my conduit was flush with the butt end of my printed mounts. That yielded a very square build, even over a 5’ by 3’ expanded area. It was great with the non-dual endstops, but I occasionally noticed my long axis becoming visibly skewed between the motors when I homed it. This is why I wants the dual endstop build. Yes, I am making signs and other fun stuff (specially now that I have Aspire for the summer)… but I am always treating it with precise offsets, and I like it It’s satisfying. Great work on this project!

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