93mm hole drilled 70' long steel bar. How hard can itbe

This is my smallest tool at 93mm. I intent to make a tool to cut 75mm.
93mm hole drilled 70' long steel bar. How hard can itbe
93mm hole drilled 70' long steel bar. How hard can itbe
93mm hole drilled 70' long steel bar. How hard can itbe

Trepanning. TREPANNING. Boring. Steel bar. Steel tube. Metal lathe. Engineering. Machine shop.,