How I do it ...
For cutting aluminum shafts I use a mini tubing cutter. A few light twists of a tapered reamer cleans up the cut end very nicely.
For carbon shafts I use a Dremel carbide cut off wheel and do it free-hand, by eye. You'd be surprised how accurate that can be. After cutting, I lightly twist the cut end over a stationary sander wheel with 120 grit, or simply use a hand held sanding block, to true up (if necessary).
In all cases I install the point inserts with slow set epoxy, which fills any ultra minute gaps 'tween insert and shaft end. Never ever had a problem with the many, many hundreds of shafts I've processed over the decades.
YMMV.