Unanswered Z offset and bed leveling questions

I am trying to print a 215 X 215 mm piece in ABS so having a precisely leveled print bed seems to be key for success. My search in this forum for tips on fine tuning bed leveling led me to have some other questions though, shocking right? First of all, my head prints at the proper height from the bed with a z offset of 0 and no M565 command of any sort in the starting G-code. I have the Robo RD+1 running Matter control 1.5 and matter slice. By all accounts these settings should not work but they do? Also, since I put blue tape on the print bed, I have been using my new favorite Baby stepping feature to raise my head by .08mm to get a good first layer. Is 0.08 what I should be using as my z-offset value? If yes, is it enough to put in that value for the z offset in the print area settings in MC or do I have to write it into the starting g-code as well? And lastly, if one has preformed the paper test on the x axis relative to the bed, both y switches click simultaneously on all parts of the bed, magnets are in place but the front left X0 Y0 corner of the bed still seems to be slightly higher than the rest, is it time to find the hole puncher or is there anything else that can be done to achieve a more precisely leveled print bed ?

 

Hi Zdot,

To change the Z offset in MC please go to controls and scroll down to Macros. From there you can adjust the Z offset. The default setting for the R1+ is 0.9mm. If you have the R1 (blue LED lights), then you would adjust it in settings under Printer>Print area>Z offset.

As far as the magnet being off, you can removce it using the putty knife or some other tool and re-gluing it to where it should be.

 

Thanks Kevin.
However what I find intriguing is that my print height seems to be just fine with a z offset of 0 when printing directly on glass... but ill try playing with it maybe it will improve the autolevel process