question about offset

Yes use the #

As to G10L20, yes I probably got it wrong (If your machine is located at the machine origin G53X0Y0, position, it would not matter the results would be the same.)

The P however needs to be P2, that will specify changing the G55 offsets.

When you said you tried to force the change them, did you manually edit the .var file and save it? That can actually work, but Linuxcnc must be closed when you make your change and save, because Linuxcnc only reads the file when opening, and will save over your changes when closing.

ah... that is probably the thing.
I was editing linuxcnc.var, while linuxcnc was running.
I made changes to vars. saved file. closed it.
then I bounced linuxcnc... those 5241 and 5242 came back like I never edited them.
ok. thank you. let me try to edit these values with CLOSED linuxcnc.

Thank you!

Thank you, Todd - that worked. so, yes... it's right - linuxcnc starts and holds linuxcnc.var in the memory.
so, whatever changes I have made linuxcnc.var, while linuxcnc is running itself cannot be read.
Thank you.
at least this mystery is solved.

The Gcode shoudt always load a TOOL
no tool is all tools
and no G53 G0 shoudt be inside

the G53 is MASHINE not workpice
only G54-G59 shoudt be present in Gcode

GET full controll
with your settings on the tooltable
and use the defaults in Preamble

Thank you andypugh!
That was the one. turned out I incorrectly measured it while running stepconf.

it looks much better now.
Thank you all for your help and suggestions.

turned out it was a bit too early to celebrate the victory.
Please, if anyone has any idea suggestion this happening.
What happened was:
I am cutting simple square 10 x 10 mm with cut offs each corner:
N0 ;(square1.ngc)
N1 G92.1(reset G92 and set values to zero)
N2 G17 (Plane Select. XY = default )
N3 G21 (use millimeters)
N4 ;G54 (select coordinate system. must be set before G42/G42)
N5 G90 (absolute distance mode)
N6 ;G40 (cancel cutter compensation)
N7 G61 (Exact path mode)
N8 F0.05 (set feed)
N9 ;G53 G0
N10 ;G54 X0.36 Y0.36
N11 G1 X1.40 Y1.00
N12 G1 X10.60 Y1.00
N13 G1 X11.00 Y1.40
N14 G1 X11.00 Y10.60
N15 G1 X10.60 Y11.00
N16 G1 X1.40 Y11.00
N17 G1 X1.00 Y10.60
N18 G1 X1.00 Y1.40
N19 G1 X1.40 Y1.00
N20 ;G40
N21 M2

cutting goes counterclockwise, so, bottom of this square is side #1.
it just finished cutting. side #1, side #2, side #4 are fine - good cut surface, all sides are in parallel, except somehow, side #3 was cut shorter. long sides of this square came out 9.40 mm(which is correct as I did not apply cutter compensation, because I wanted to get first simple cut and then figure out offsets). but, side #3 is 5.6mm.
linuxcnc reported during the cutting that it went all the way to the end of this side.
only thing I did was I paused last night the machine when side #2 and its corner were done and left it paused for overnight. this morning I resumed cutting. cutting finished at the point where it supposed to (well with certain precision about 0.1mm).
why only one side (#3) was cut shorter?
any ideas? suggestion?
PLEASE!

I am sorry, picture of what?