PCB Eagle plugin pcb-gcode-3.6.0.4

Here are the results of the tutorial3. The circuit on the left was done with 1/64 inch tool. The circuit is not correct.
The circuit on the right was done with 1/100 inch tool. The difference of colors is due to the layer that tool has reached. The board is not probably perfectly square. I tested the isolation and the board seems OK. The copper has been removed everywhere it needed to be.
Lesson learn:
-I try first with engraving tools from inventables https://www.inventables.com/categories/bits-tools/milling-bits?utf8=✓&selected_filters[Type][]=PCB+Milling+Bits
It’s cheap but they don’t do the job: air cut after 1 cm.
-The quality of the cutting tool is essential and the smaller the better. I use a 0.010 2 FL SQ Micro EM from Kodiak
-The tape is very difficult to remove from the PCB. Need to find another way to secure the PCB on the wasteboard.
-Need to buy some EM2E8-0945-30VC used by David @perduedt

Thanks David for your post, I used the same parameters.