I have named this post "Powerful precise and mobile CNC for steel milling". Today I am able to confirm the successful trial of a 3/4" (19.05mm) diameter, 3 flute index carbide. At 5mm cut width it seems to perform better than any end mills I he tried so far. This video quantifies the "powerful" statement "youtu.be/xQEiCTPRw9U"
The video for "precise" statement is included in the following 2 videos: "youtu.be/B0wCOuC_nGQ" and "youtu.be/xdfABHCaOdE"
I have search for some time for a machine with similar performance. Because I did not find one, I will call my machine "The 1st steel milling low mass CNC".
https://youtu.be/xQEiCTPRw9U
https://youtu.be/B0wCOuC_nGQ
https://youtu.be/xdfABHCaOdE