3dtouch and bed leveling ... (no replies)

I have a Geeetech i3 Pro C (acrylic) - and yes I have a 3dtouch rather than a bltouch, but it has proved to produce consistant measurements YMMV.

However, I have been struggling for a long time to get bilinear leveling to work.

There is no detectable twist in the x-axis and the 3dtouch has zero y axis offset to the nozzle, the bed is reasonably level by the "paper" test, and the printer prints reasonably well with just manual leveling.

But no matter what I tried any attempt to print using bilinear leveling ALWAYS gave a nozzle too low on the left and too high on the right.

I even ran the debugging options but there was no obvious problem that I could see.

It then occured to me that there are magnets in the steppers and the X axis stepper is on the left ... ?? so I though of trying a shield.
In investigating how to do this I noticed my screwdriver tended to stick to the lower x axis rail - but only at the left end !!!

I demagnetized the x-axis rails and low and behold it's a whole lot better !!!

I dont know if this also applies to the BlTouch ... but it's worth bearing in mind!

I hope this helps someone else,
Dave