MiniDrill-GFF FinFan : How to repair the plug and the plug seat in the FinFan gas cooler?

MiniDrill-GFF FinFan is a unique machining
platform designed to safely perform the repair
or increase the FinFan Cooler plug thread and
other operations on heat exchangers, boilers
and similar thermal exchange equipment.
Designed with operator safety in mind,
this system can drill, ream, bore, and even
re-machine serrations in steam drums quickly
and safely. With an 80 mm (3.150”) travel, this
tool is ideally suited for the majority of plant
equipment. The system is fully torque reacted
with 2 clamping arms that are independent of
one another and can accommodate most pitch
configurations. Once locked into the tubes, the
MiniDrill-GFF is extremely stable.