Minecraft: 1.12.2
Forge: 14.2.5.2815
Tech Reborn: 2.20.13.940
Reborn Core: 3.13.5.421

The drill still does 3x3 mining and quite fast even with 0% energy. This was tested with clean install and no mod settings changed nor any vanilla other than sound/video/controls.

IMO it should mine a lot slower and only 1x1 when out of power if not at all.

Not sure about other tools/weapons.