Having had a couple air hammers for 50+ years, including
the pointed chisel used in the video, my experience doesn’t leave me with any
concern of damaging the crankshaft or bearings. However lifting the flywheel is
standard procedure with any method other that using a puller. I suspect what is
really separating the crankshaft from the flywheel is the harmonics that are
being created. Much the same as an extremely loud note, at the right resonant
frequency, that can make a glass vibrate, to the point it breaks.
Tubs.
A "Boathouse Repair" is one thats done without having tools or the skills to do it properly.